Economics Notes | B.A. LL.B. (Five Year Course) Semester 1 | Mumbai University | munotes

The definitions, and why there are four of them

There is no single agreed definition of economics, and an examiner who asks you to define the subject expects you to know that and to know why. The definitions differ because their authors disagreed about what the subject is centrally about. Four families matter, and they arrived in this order.

The wealth definition: Adam Smith, 1776. Smith, a Scottish moral philosopher, published An Inquiry into the Nature and Causes of the Wealth of Nations, and the title states the definition. Economics, for Smith and for the classical writers who followed him, is the science of wealth: what makes a nation rich, and what makes it poor. The great insight of the book is that a society grows rich through the division of labour and through exchange, and that individuals pursuing their own advantage are led, as if by an invisible hand, to serve an end that formed no part of their intention.

Why it was attacked. Critics said the wealth definition made the subject sordid, a "gospel of Mammon", because it put material goods at the centre and human beings at the edge. Thomas Carlyle called economics the dismal science. The complaint was that a science of wealth says nothing about whether the wealth does anybody any good.

The welfare definition: Alfred Marshall, 1890. Marshall's Principles of Economics moved the human being to the centre. Economics, on his view, studies people in the ordinary business of life: how they earn a living and how they use what they earn. Wealth matters, but only as a means to material welfare. Two features of this definition are examinable. It is a study of humanity first and of wealth second, and it is limited to material welfare, which is welfare that can be measured in money.

Why it too was attacked. Marshall's line between material and non material welfare will not hold. A doctor's advice and a lawyer's opinion are not material, yet nobody would leave them out of the national income. And the word welfare smuggles in a judgment about what is good, which is not a scientific question at all.

The scarcity definition: Lionel Robbins, 1932. Robbins, in An Essay on the Nature and Significance of Economic Science, gave the definition most textbooks now start from. Economics, he said, is the science that studies human behaviour as a relationship between ends and scarce means which have alternative uses. Three conditions have to hold together before a problem is an economic problem at all, and an answer that lists them scores well.

1. The ends, meaning the wants, are many.
2. The means, meaning the resources, are scarce in relation to those ends.
3. The means have alternative uses, so that using them one way rules out another.

If any one condition fails there is no economic problem. Air is scarce nowhere in the ordinary sense and so is not an economic good, although clean air in a city is becoming one, which shows how the definition works. Robbins's definition is neutral: it does not ask whether the end is worthy, only how scarce means are matched to competing ends.

Why it too was attacked. By refusing to judge ends, Robbins made economics unable to say that feeding a starving family matters more than a rich family's fourth car. He also left out growth: his definition describes the allocation of a fixed quantity of resources at a moment, not the increase of resources over time.

The growth definition: Paul Samuelson, from 1948. Samuelson's textbook definition supplies what Robbins left out. Economics studies how people and society choose, with or without money, to employ scarce productive resources that could have alternative uses, to produce various commodities over time, and to distribute them for consumption now and in the future among various people and groups in society. The two additions are the words over time, which bring in growth, and the reference to distribution, which brings back the question of for whom.

The safest answer in an exam takes the four in order, gives the author and the date of each, says in one sentence what each added, and closes by saying that modern economics works with a scarcity definition of Robbins's kind widened by Samuelson to include growth.

The nature of economics: is it a science?

MU asks about the nature of economic science, so the question has to be met directly rather than assumed.

It has the marks of a science. It proceeds from observation to generalisation. Its statements are meant to be testable against evidence that somebody else could collect. It uses measurement heavily, and it has laws in the scientific sense of regularities that hold when stated conditions hold, such as the law of demand in [Demand and the Law of Demand].

It is not a science of the physical kind, and for four reasons.

1. It cannot run controlled experiments. A chemist can hold everything constant but one thing. An economist studying the effect of a tax cannot stop the weather, an election or a war happening at the same time. This is why the phrase "other things being equal" appears in every economic law: it is an assumption, not a result.
2. Its material is human beings, who change their behaviour once they know the prediction. If everybody believes prices will rise tomorrow, they buy today, and prices rise today instead.
3. Its measurements are approximations. National income is estimated and revised three times, as [The Difficulties of Measuring National Income in India] shows.
4. Its predictions are conditional and rarely precise. It can say which way a quantity will move more reliably than by how much.

Is it a positive science or a normative one? This is the second half of MU's topic 1.1 and it has its own chapter, [Positive and Normative Economics]. The short answer is that it is both, and that the two must be kept apart when writing.

Is it an art? An art is the practical application of knowledge to achieve a result. Economics has that side too: a finance minister framing a Budget is practising an art on the basis of a science. The examiner's expected answer is that economics is both a science and an art, and that treating it as only one of the two produces either theory nobody can use or policy nobody can defend.

The significance of economics

The second half of MU's label asks why the subject matters. Four answers, in ascending order of usefulness to a law student.

To the individual. It explains the choices a person makes every day without naming them: whether to rent or buy, whether to take the job or the further degree, why the price of onions moves the way it does.

To business. Costs, pricing, market structure and forecasting are economic questions before they are management questions.

To the State. Every Budget, every tax, every subsidy, every interest rate decision and every trade agreement is an economic decision taken by a public authority under law. Modules II, III and IV of this syllabus are entirely about that.

To the citizen and the lawyer. A person who cannot read an economic argument cannot evaluate a policy, a judgment on economic regulation, or a claim about who is being helped and who is paying. That last is the subject of the next chapter.

A worked example: Anjali's field

Anjali farms four acres near Nashik. She can plant grapes, which she expects to earn her three lakh rupees this year, or tomatoes, which she expects to earn her one lakh eighty thousand. She has enough labour and water for one crop, not both.

The economic problem, stated in Robbins's three parts. Her ends are many: income now, a wedding to pay for next year, a pump she wants to replace. Her means, four acres and one season's water, are scarce against those ends. And the means have alternative uses, because the same acre grows either crop.

The choice. She plants grapes. Her gain is three lakh rupees.

The opportunity cost. The cost of that decision is not the seed, the labour and the fertiliser alone. It is also the one lakh eighty thousand rupees of tomatoes she did not grow, because that is what she gave up to grow grapes. Opportunity cost is the value of the next best alternative given up when a choice is made, and it is the single most useful idea in the subject. It is the reason a decision that looks profitable can still be a bad decision.

Why a lawyer should notice. When a court awards damages for a crop lost to a canal breach, it is being asked to value exactly this. If it compensates Anjali only for her seed and labour it has ignored opportunity cost and undercompensated her. If it awards the grape revenue with no deduction for the costs she saved, it has overcompensated her.

What economics is NOT

Three corrections, because each of them is a mistake beginners make and re-reading does not cure them.

It is not the study of money. Money is one institution studied within economics, in [What Money Is, and Why Its Supply Is Measured]. Barter economies had economic problems and no money at all.

It is not the same as commerce or accountancy. Accountancy records what happened to one firm. Economics explains behaviour across an economy and predicts it.

It is not a set of opinions about what the government should do. That is the normative half, and it depends on the positive half being got right first. Somebody who has an opinion about a farm law but cannot say what happens to price when supply rises is not doing economics.

The vocabulary, defined once here

Every later chapter uses these without stopping. Learn them now.

Goods and services. A good is a tangible thing that satisfies a want: rice, a phone, a house. A service is an intangible one: a haircut, a train journey, legal advice. Free goods are available without cost in the quantity wanted, such as sunlight. Economic goods are scarce and command a price. Consumer goods are wanted for their own sake; capital goods, such as a machine or a factory, are wanted because they help produce other goods.

Wants. A desire for a good or service. Wants are unlimited, recur, are competitive with one another, and become habits. Necessaries are wants that must be met to live or to work; comforts make life easier; luxuries go beyond that. The classification is relative: a mobile phone was a luxury and is now closer to a necessity.

Utility. The capacity of a good to satisfy a want. It is not the same as usefulness and carries no moral judgment: liquor has utility for a person who wants it. Marginal utility is the addition to total utility from consuming one more unit. The law of diminishing marginal utility says that as a person consumes more units of the same good in one stretch, each extra unit gives less satisfaction than the one before. That law is the foundation of [Demand and the Law of Demand].

Factors of production. The resources used to produce anything, traditionally four. Land means all free gifts of nature, including minerals and rivers, and its reward is rent. Labour is human effort, mental or physical, done for a reward, and its reward is wages. Capital is produced means of production, meaning wealth used to produce more wealth, such as tools, machinery and stocks of raw material, and its reward is interest. Enterprise is the function of organising the other three and bearing the risk of loss, and its reward is profit. Capital in economics means machines and stocks, not money in a bank; money is finance, not capital.

Production, consumption, exchange and distribution. The four branches of the subject. Production is the creation of utility; consumption is its use up; exchange is the transfer of goods between people; distribution is the division of the total product among the factors that made it.

Wealth, income and welfare. Wealth is a stock of goods that are scarce, transferable and have utility, measured at a moment. Income is a flow received over a period. Welfare is the satisfaction people get, which wealth and income only imperfectly measure.

The margin. Economics almost never asks "should this be done" but "should one more unit of it be done". The extra unit is the marginal unit, and marginal thinking is the habit the whole subject is built on.

Ceteris paribus. A Latin phrase meaning other things being equal. When an economic law says that a fall in price raises the quantity demanded, it means: on the assumption that income, tastes, the prices of other goods and everything else stay where they are. An economic law with this assumption stripped out is not a stronger claim, it is a false one.

Limits and criticism

It cannot settle a value question. Whether the State should tax the rich more is a question about fairness. Economics can say what a tax would collect and how behaviour would change; it cannot say what ought to be done, and a writer who pretends otherwise has slipped from the positive into the normative without saying so.

Its assumptions are strong. Much of the theory in this module assumes people are informed and self interested and that they weigh alternatives. Real people use rules of thumb, misjudge risk and are influenced by how a choice is put to them. The field of behavioural economics grew out of exactly this criticism.

Its laws are tendencies, not certainties. They state what happens if nothing else changes, and something else always changes.

Aggregates hide people. A rise in per capita income is consistent with most people becoming poorer, if the gains go to a few. This is why [Poverty and the Poverty Line] measures the distribution as well as the average.

Quick revision

1. The economic problem is unlimited wants against scarce means that have alternative uses. Everything else follows from it.
2. Opportunity cost is the value of the next best alternative given up. It is the cost that matters in economics and the one accounts leave out.
3. Four definitions in order: Adam Smith 1776, wealth; Alfred Marshall 1890, material welfare; Lionel Robbins 1932, scarcity and choice; Paul Samuelson from 1948, scarcity plus growth over time.
4. Robbins's three conditions: ends are many, means are scarce, means have alternative uses. All three must hold.
5. Four central questions: what to produce, how, for whom, and is the economy efficient and growing.
6. Nature: a social science, both positive and normative, and an art as well when it is applied to policy. It cannot experiment, its subject matter reacts to prediction, and its laws carry the assumption of other things being equal.
7. Four factors of production and their rewards: land and rent, labour and wages, capital and interest, enterprise and profit.
8. The law of diminishing marginal utility is the foundation of demand theory.
9. MU's topic label is the title of Robbins's 1932 book, which is a useful thing to notice in an answer.

Test yourself

1. Define economics in the way Robbins did, and state the three conditions his definition requires. Economics is the science which studies human behaviour as a relationship between ends and scarce means that have alternative uses. Three conditions must hold together: the ends must be many, the means must be scarce relative to those ends, and the means must have alternative uses. If any one fails there is no economic problem, which is why air in the open is not an economic good and clean air in a city is becoming one.

2. What is opportunity cost? Illustrate with an example that is not from this chapter. Opportunity cost is the value of the next best alternative sacrificed when a choice is made. A student who spends a year on an unpaid internship bears, as opportunity cost, the salary of the job they could have taken. It matters because a course of action that shows an accounting profit can still be a loss once what was given up is counted.

3. Distinguish Marshall's definition from Robbins's, and say what each was criticised for. Marshall defined economics as the study of people in the ordinary business of life, concerned with the part of individual and social action most closely connected with the attainment and use of the material requisites of wellbeing; it puts human welfare at the centre and is limited to material welfare. It was criticised because the line between material and non material welfare cannot be drawn, and because welfare is a value judgment. Robbins defined economics by scarcity and choice and made it neutral between ends; he was criticised for that very neutrality, which leaves the subject unable to say that one end matters more than another, and for leaving growth out.

4. Is economics a science? Give the argument on both sides and a conclusion. It has the marks of a science: it generalises from observation, states testable propositions and has laws that hold under stated conditions. It differs from a physical science in four ways: it cannot run controlled experiments, its subject matter is human beings who react to predictions, its measurements are approximations, and its predictions are conditional. The conclusion usually expected is that it is a social science, and also an art when applied to policy, and that its laws are tendencies stated on the assumption that other things are equal.

5. Name the four factors of production and the reward of each. Land, rewarded by rent; labour, rewarded by wages; capital, rewarded by interest; and enterprise, rewarded by profit. Capital in economics means produced means of production such as machinery and stocks, not money.

6. What is meant by ceteris paribus, and why does every economic law carry it? It is Latin for other things being equal. Economic laws state what one variable does to another when everything else is held constant, because in the real world several things move at once and no controlled experiment is possible. Removing the assumption does not make the law stronger; it makes it false.

7. State the four central questions every economy must answer, and say how India answers them. What to produce, how to produce it, for whom to produce it, and whether resources are fully and efficiently used and growing. A market economy answers through prices, a planned economy through a central authority. India answers through both, using markets for most production and the State for planning, regulation, taxation and redistribution, which is what is meant by calling it a mixed economy.

• Monopoly. A single seller charges more and produces less than a competitive industry would. The Competition Act 2002 answers it. Section 4(1) says no enterprise or group shall abuse its dominant position, and section 4(2) lists what abuse means: unfair or discriminatory prices including predatory prices, limiting production or technical development, denial of market access, tying, and using dominance in one market to enter another. [Monopoly] works through the economics that provision is built on.
• Externalities. An externality is a cost or a benefit that falls on somebody who is not a party to the transaction. A factory's effluent is a cost borne by villagers downstream who never bought the product. The whole of environmental law, and much of the law of nuisance, exists to put that cost back on the person who caused it.
• Public goods. A public good is one that nobody can be excluded from and that one person's use does not diminish, such as street lighting or national defence. No private seller can profitably supply it, because everybody can enjoy it without paying. So the State supplies it and taxes to pay for it, which is the subject of [The Sources of Public Revenue] and [Public Expenditure and Its Classification].
• Information asymmetry. One side of a bargain knows more than the other. Consumer protection law, the duty of disclosure in insurance, and the disclosure requirements in a prospectus all answer it.

4. Courts and tribunals must value things. Damages for a lost crop, compensation for land acquired, maintenance under a matrimonial statute, the multiplier in a motor accident claim, the compensation for a lost limb: every one of these is a valuation, and valuation is an economic operation. [What Economics Is] introduced opportunity cost for exactly this reason. A court that compensates only out of pocket expenses has ignored the value of the alternative the claimant gave up.

5. Legislation is drafted to economic objectives, and its success is measured in economic terms. The Insolvency and Bankruptcy Code was passed to move assets out of unproductive hands faster. The goods and services tax was designed to remove the tax on tax that a chain of separate State levies produced. A lawyer who cannot state the economic object of a statute cannot argue about its interpretation when the words run out.

The distinction that matters most: efficiency and equity

Two words do most of the work when law and economics meet, and they are not the same word.

Efficiency asks whether the total quantity of value produced is as large as it can be, whatever its distribution. An arrangement is efficient in the ordinary economic sense if no change can make somebody better off without making somebody else worse off.

Equity asks who gets what, and whether the division is fair.

A rule can be efficient and unfair, or fair and wasteful. A land ceiling law that redistributes holdings may reduce total output and still be defended on equity. A rule that lets a factory pollute freely may maximise output and be indefensible.

Law almost never chooses efficiency alone. Article 39 puts distribution in the Constitution, and a student who answers a question about a welfare statute purely on efficiency has answered half of it.

A worked example: a rent control law in Mumbai

Mr Kulkarni owns four flats in a building in Dadar. Mrs Fernandes is a tenant in one of them. A statute is passed freezing rents at their 1999 level and giving tenants an indefinite right to remain.

What the lawyer sees. A protective statute that secures a home for a tenant of modest means against a landlord who has other flats. The purpose is unmistakable and, on its own terms, achieved: Mrs Fernandes cannot be evicted and her rent cannot rise.

What the economist adds, in four steps.

1. The price is now below the market price, so the quantity demanded exceeds the quantity supplied. This is the excess demand of [How Demand and Supply Together Set a Price].
2. The landlord's incentive to supply changes. Mr Kulkarni will not offer his three vacant flats on rent at all. He will keep them empty, sell them, or let them only to somebody who pays a large lump sum in advance that the statute does not reach.
3. The shortage is rationed by something other than price, and usually by whatever the law does not regulate: a premium, a personal connection, or a willingness to sign a licence rather than a lease.
4. The stock decays. A rent that cannot rise will in time not cover repairs, so buildings under long rent control are conspicuously worse maintained than buildings outside it.

The point of the example. None of this shows that the statute is wrong. Mrs Fernandes has a home she would otherwise have lost, and that is an equity gain the economics does not measure. What the economics shows is that the statute has a second set of effects, falling on people who are not before the court, and that a lawyer who argues only the first set will be surprised by the second. A well drafted statute anticipates them: this is why modern rent legislation usually permits periodic revision and distinguishes new tenancies from old ones.

Where the two subjects genuinely disagree

Three honest disagreements, which are worth a paragraph in an answer because they show the relationship is not one of servant and master.

Economics tends to treat people as consistent maximisers. Law knows they are not, which is why it has doctrines of undue influence, unconscionability and consumer protection.

Economics values outcomes. Law also values process. A trial that reaches the right result by the wrong procedure is a failure in law and a success in economic terms.

Economics has no place for rights that cannot be traded. Law has many: the right to personal liberty, the right against forced labour. An analysis that prices everything has misunderstood what a right is.

What this chapter does NOT claim

It does not claim that economics decides legal questions. It supplies a prediction and a valuation. The choice of objective is made by the Constitution, the legislature and the court.

It does not claim that the efficient answer is the right answer. See the distinction above.

It does not claim that a lawyer needs mathematics. Everything in this book can be done in words and simple arithmetic.

Quick revision

1. Five connections: law creates the framework markets need; every rule changes costs and so changes behaviour; much of the law answers a market failure; courts must value things; and statutes are drafted to economic objectives.
2. Four market failures: monopoly, externalities, public goods, information asymmetry. Each has a body of law answering it.
3. Constitution, article 39(b) and 39(c): distribution of material resources to subserve the common good, and prevention of concentration of wealth and the means of production to the common detriment. These put economics into the Constitution.
4. Competition Act 2002, section 4(1): no enterprise or group shall abuse its dominant position. Section 4(2) lists the forms of abuse.
5. Efficiency against equity: efficiency asks how large the pie is, equity asks how it is cut. Law weighs both; an answer that uses only one is half an answer.
6. The rent control example is the standard illustration: an intended effect on the tenant before the court, and unintended effects on people who are not.

Test yourself

1. State four reasons why a law student is required to study economics. Because the law supplies the framework, contract, property, currency and corporate personality, without which markets cannot function; because every legal rule alters the costs facing those it binds and so alters their behaviour, often in ways the drafter did not intend; because a large part of the law exists to correct market failures such as monopoly, externalities, public goods and information asymmetry; and because courts must value losses and fix compensation, which is an economic exercise. A fifth reason is that statutes are drafted to economic objectives and their interpretation turns on those objectives.

2. Which articles of the Constitution place an economic objective on the State, and what do they say? Article 39(b) directs the State to secure that the ownership and control of the material resources of the community are so distributed as best to subserve the common good. Article 39(c) directs it to secure that the operation of the economic system does not result in the concentration of wealth and means of production to the common detriment. Both are directive principles in Part IV, so they guide legislation and are not directly enforceable by a court.

3. What is a market failure? Name four kinds and the law that answers each. A market failure is a situation in which a market left to itself does not produce the outcome society wants. Monopoly, answered by the Competition Act 2002 and in particular section 4 on abuse of dominant position; externalities, answered by environmental law and the law of nuisance; public goods, answered by public provision financed from taxation; and information asymmetry, answered by consumer protection law and by disclosure duties in insurance and in company prospectuses.

4. Distinguish efficiency from equity, and give an example of a rule that is one and not the other. Efficiency concerns the size of the total product and asks whether resources are being used so that nobody can be made better off without somebody being made worse off. Equity concerns the distribution of that product. A law permitting a factory to discharge effluent without treatment may raise total output and is inequitable to those downstream; a land ceiling law may reduce total output and be defended as equitable. Legal systems choose a mixture, and in India article 39 makes distribution a constitutional objective.

5. A statute freezes rents. Describe the economic effects a lawyer should anticipate. The controlled rent lies below the market rent, so the quantity of housing demanded exceeds the quantity supplied and a shortage appears. Landlords withdraw units from the rental market or let them only on terms the statute does not reach, so new tenants find it harder to rent at all. Rationing shifts to non price devices such as premiums and personal connections. And maintenance falls, because a frozen rent eventually fails to cover repairs. The tenant already in occupation gains; prospective tenants and the housing stock lose.

6. Give one respect in which economic reasoning does not fit the law, and explain it. Economics values outcomes and is largely indifferent to procedure, while law treats fair procedure as a value in itself: a decision that happens to be correct but was reached without hearing the affected party is a failure in law. A second respect is that some legal rights are deliberately not tradeable, such as the right against forced labour, so an analysis that treats every entitlement as having a price has misdescribed them.

Why you cannot simply add the parts up: the fallacy of composition

This is the deepest point in the chapter and the one that most often appears as a short note question.

The fallacy of composition is the mistake of assuming that what is true of a part must be true of the whole. It is the reason macroeconomics had to be invented as a separate branch.

Example one, the paradox of thrift. If one household saves more, that household becomes better off. If every household saves more at once, total spending falls; falling spending means falling sales; falling sales mean lower output and fewer jobs; and with lower incomes the total amount actually saved may end up smaller than before. What is prudent for one is damaging for all.

Example two, wages. A single firm that cuts wages lowers its costs and can sell more. Every firm cutting wages at once lowers the incomes of the very people who buy the goods, so demand falls and the firms may end up selling less.

Example three, from outside economics. One person standing up at a cricket match sees better. Everybody standing up sees no better and is less comfortable.

The reverse mistake exists too and is called the fallacy of division: assuming that what is true of the whole must be true of each part. National income can rise in a year in which most people become poorer, if the gain is concentrated.

They are not rivals: the two are interdependent

An examiner sometimes asks whether the two branches are opposed. They are not, and the answer has two halves.

Macro rests on micro. Aggregate demand is the sum of the demands of individual households and firms. The general price level is an average of individual prices. Any macroeconomic proposition eventually has to be consistent with how individuals behave, which is what economists mean when they speak of the microeconomic foundations of macroeconomics.

Micro rests on macro. No firm can plan without knowing what is happening to the whole economy. A monopolist's demand curve shifts when national income changes; a builder's costs shift when the interest rate does. A firm studied with the rest of the economy held constant is being studied under an assumption everybody knows is false, which is the standing limitation of partial equilibrium analysis.

The picture usually offered is that microeconomics examines the trees and macroeconomics examines the forest. Neither view alone tells you what is happening to the wood.

A worked example: one onion farmer and the price of onions

Sunil grows onions on two acres near Nashik. In a good monsoon his yield is heavy.

The micro question. With a heavy crop, the supply of onions in the Lasalgaon market rises. With demand unchanged, the price of onions falls. Sunil's revenue may fall even though his output rose, if demand for onions is inelastic, which is the trap explained in [Elasticity of Demand]. That is a complete microeconomic analysis: one market, one relative price, the rest of the economy held constant.

The macro question is a different question. Does a heavy onion crop reduce inflation? Now the unit is the general price level, not the price of onions. Onions have a weight in the consumer price index. A fall in their price pulls the index down by that weight, but only if other prices do not rise at the same time. If the monsoon also raised transport costs or if fuel prices rose that month, the index can rise while the onion price falls.

What the example shows. The same event answers two different questions, with two different units of study, two different methods, and two different sets of things held constant. Notice also the direction of influence: if the general price level rises sharply, the government may ban onion exports, which changes Sunil's market. Macro conditions feed back into the micro answer.

What beginners get wrong

"Micro means small quantities and macro means large ones." No. The subject of study is what differs, not the size of the number. The total sales of a single very large company are a microeconomic quantity. The average price of a matchbox across the country is a macroeconomic one.

"Micro is about firms, macro is about government." No. Macroeconomics studies household consumption and business investment too. Government is one of four sectors in [The Circular Flow of Income].

"They contradict each other." No. They answer different questions. Where they appear to contradict, the usual cause is the fallacy of composition.

"Macro came first because it is more general." No. Micro is the older branch; macro was built later, out of the Depression.

Limits of each branch

Microeconomics assumes full employment far too readily, treats the rest of the economy as constant when it never is, and cannot answer questions about the economy as a whole. It also says nothing about growth over time.

Macroeconomics works with aggregates that hide their own composition. A stable general price level can conceal a sharp rise in food prices and a sharp fall in electronics prices, which matter very differently to a poor household. An average is not a description of anybody.

Quick revision

1. Microeconomics studies individual units: a consumer, a firm, an industry, one market. Also called price theory. It works with relative prices and partial equilibrium.
2. Macroeconomics studies the economy as a whole: national income, employment, the general price level, money and the balance of payments. Also called income and employment theory.
3. The words were coined by Ragnar Frisch in 1933; the branch of macroeconomics was built by Keynes in the General Theory, 1936, out of the Great Depression.
4. The fallacy of composition: what is true of a part need not be true of the whole. The paradox of thrift is the standard example. Its reverse is the fallacy of division.
5. They are interdependent. Macro is built on micro behaviour; micro analysis holds macro conditions constant that in fact move.
6. In this syllabus: Module I topics 1.2 and 1.3 are micro; topics 1.4 to 1.6 and Modules II, III and IV are macro.

Test yourself

1. Define microeconomics and macroeconomics, and name the economist who coined the two terms. Microeconomics analyses the behaviour of individual economic units, a consumer, a firm, an industry or a single market, and explains relative prices and the allocation of resources between uses. Macroeconomics analyses the economy in the aggregate and explains national income, total output, total employment, the general price level, the money supply and the balance of payments. Both words were introduced by Ragnar Frisch in 1933.

2. Give five points of difference between the two branches. Unit of study, an individual unit against the whole economy; alternative name, price theory against income and employment theory; central variables, relative prices and individual demand and supply against national income, aggregate demand and the general price level; method, partial equilibrium with other things held constant against general equilibrium; and treatment of employment, which micro usually assumes to be full and macro sets out to explain.

3. What is the fallacy of composition? Illustrate it. It is the error of inferring that what is true of a part is necessarily true of the whole. The paradox of thrift is the classic illustration: additional saving makes one household better off, but if all households save more at once, spending and therefore incomes fall, and total saving may end up lower than before. A second illustration is a wage cut, which helps one firm's sales and damages all firms' sales if every firm does it.

4. Why did macroeconomics develop as a separate branch? Because classical reasoning built up from individual markets predicted that unemployment would cure itself through falling wages, and in the Great Depression of the 1930s it did not, for years together. Keynes argued in the General Theory of 1936 that questions about total output and total employment cannot be answered by adding up answers about single markets, because of effects like the fallacy of composition.

5. Are the two branches independent of each other? Explain. No. Macroeconomic aggregates are built out of individual behaviour, so every macroeconomic proposition must be consistent with how households and firms actually act. Conversely, microeconomic analysis holds constant things, national income, interest rates, the price level, that macroeconomic forces are constantly moving, so a partial equilibrium answer is only as good as that assumption. They are two levels of the same subject.

6. Classify these as micro or macro: the price of petrol in Mumbai; the rate of inflation; the wage of a welder; the fiscal deficit; the demand for a company's product. The price of petrol in one city, micro. The rate of inflation, macro, because it measures the general price level. The wage of a welder, micro, since it is one factor price. The fiscal deficit, macro. The demand for one company's product, micro.

The distinctions table

A worked example: a minimum wage in a small town

Sridhar runs a workshop with eleven workers in Bhiwandi. A notification raises the minimum wage for his class of establishment.

Four statements are made in the debate. Sort them.

1. "After the notification, Sridhar's wage bill rose by eighteen per cent." Positive. Verifiable from his books.
2. "He responded by not replacing two workers who left." Positive. Verifiable, and it is a claim about behaviour.
3. "A higher minimum wage reduces employment among the least skilled." Positive, and much harder. It is a general claim about cause and effect, and economists genuinely disagree about its size because the evidence is mixed. That the answer is contested does not make the statement normative; it makes it a difficult positive question.
4. "Nobody should have to work for less than a living wage." Normative. No study settles it.

Why the sorting matters to a lawyer. If the notification is challenged, statements 1 to 3 belong to evidence and statement 4 belongs to the object of the statute and to the constitutional standard. A petitioner who leads only statement 4 has produced no evidence. A State that answers only with statement 4 has not met the evidence. Courts routinely have to do exactly this sorting, and doing it badly is how a hearing turns into an exchange of opinions.

Where the distinction gets blurred, and an examiner will test you on it

An answer that says only "positive is what is and normative is what ought to be" is worth half marks. The rest of the marks are here.

A positive statement can carry a hidden value judgment in its choice of subject. An economist who studies the effect of a subsidy on the fiscal deficit and never studies its effect on child nutrition has made a judgment about what is worth measuring. Selection is not neutral even where measurement is.

The line between the two is not always clean. Saying "this policy is efficient" sounds positive and is usually said as praise. Efficiency is a criterion with a value built into it, namely that a larger total is better, which is precisely the point [Why a Law Student Studies Economics] makes about efficiency and equity.

A normative conclusion needs a positive premise. "The tax should be raised" is worthless unless we know what raising it does. Bad normative economics is nearly always bad positive economics wearing a moral tone.

Most real policy statements mix the two in one sentence, and unpicking them is the skill. "The fuel subsidy is a wasteful giveaway that costs the exchequer a lakh crore" contains a positive claim about a number and a normative claim in the word wasteful, and the two must be answered separately.

What this does NOT mean

It does not mean normative economics is unscientific rubbish. Every policy decision is normative. Somebody has to decide what the objective is. The point is to know which kind of statement you are making.

It does not mean an economist should have no opinions. It means the opinion should be labelled as one.

It does not mean positive statements are always true. They are testable, which is a different thing. A positive statement can be confidently made and completely wrong.

Quick revision

1. Positive economics describes and predicts. It is testable in principle and free of value judgments. Form: if A then B.
2. Normative economics prescribes. It rests on value judgments and cannot be settled by evidence. Form: A ought to be done.
3. The test: could evidence in principle show this to be false? If yes, positive.
4. Marker words for normative: should, ought, fair, just, desirable, too high. The marker is a clue, not the test.
5. Origin: Nassau Senior, then John Neville Keynes in 1890 who separated a positive science, a normative science and an art. Robbins pressed the separation; Friedman argued in 1953 that many apparently normative disputes are really positive ones in disguise.
6. The blurring points, worth marks: the choice of what to study is itself a judgment; efficiency is a criterion with a value in it; every normative conclusion needs a positive premise; and real statements mix the two.
7. For a lawyer: evidence answers positive questions, and the object of the statute and the constitutional standard answer normative ones.

Test yourself

1. Define positive and normative economics and give one example of each. Positive economics deals with statements of fact about economic behaviour which can in principle be verified or falsified by evidence, for example that an increase in the price of a good reduces the quantity of it demanded. Normative economics deals with statements about what ought to be, resting on value judgments, for example that essential medicines ought to be exempt from tax. The first can be tested; the second is a question of what we value.

2. Classify each of these: (a) India's fiscal deficit was higher last year than the year before; (b) the fiscal deficit is too high; (c) a larger fiscal deficit raises interest rates; (d) the government ought to spend more on primary schools. (a) Positive, a statement of fact checkable in the Budget documents. (b) Normative, because "too high" appeals to a standard of what is desirable. (c) Positive, a causal claim that evidence can test even though economists dispute its size. (d) Normative.

3. "A disagreement about policy is always a disagreement about values." Discuss. It is often not. Friedman's argument in 1953 was that many policy disputes between people who share the same objective turn on a positive question about what a measure actually does. Two people who both want less poverty may disagree about a minimum wage because they disagree about its effect on employment, which is a factual question capable of investigation. Some disputes are genuinely about values, for example how much present consumption should be given up for future generations, and those cannot be settled by data. The useful discipline is to separate the two before arguing.

4. Can positive economics be entirely free of value judgments? Give your reasons. Not entirely. The measurement of a relationship can be neutral, but the choice of which relationships to measure, which variables to include and which effects to report is a judgment about what matters. Terms that appear technical, such as efficiency, also carry a criterion of what is better. The honest position is that positive economics can be much freer of value judgments than normative economics, and that the judgments it does contain should be stated rather than hidden.

5. Why is the distinction useful to a lawyer? Because a court hears both kinds of statement in a single argument and must treat them differently. Claims about what a measure does are matters of evidence, to be proved by data and expert testimony. Claims about what ought to be done belong to the object of the statute, to the directive principles and to the constitutional standard of reasonableness. Separating them shows which parts of a case need proof and which need argument, and it exposes a submission that offers a value judgment where evidence was required.

6. Restate this sentence, separating its positive and normative parts: "The petrol subsidy is a wasteful giveaway costing the exchequer a lakh crore." The positive part is the claim that the subsidy costs the exchequer approximately one lakh crore rupees, which can be checked against the Budget's subsidy statement. The normative parts are "wasteful" and "giveaway", which assert that the money would be better spent otherwise and that the recipients do not deserve it. The positive claim is answered with figures; the normative claim is answered by arguing about who benefits and what else the money would buy.

2. The income effect. When the price of a good falls, the buyer's real income rises: the same money now buys more. Part of that increased purchasing power is spent on the good whose price fell. When the price rises, real income falls and less is bought.

3. The substitution effect. When the price of a good falls, it becomes cheaper relative to its substitutes, so buyers switch to it from those substitutes. When tea becomes dearer, some tea drinkers move to coffee.

4. New buyers enter. A high price excludes people who cannot afford it at all. As the price falls, households that were priced out come into the market, so the market quantity rises for a reason that has nothing to do with any existing buyer changing their mind.

5. Multiple uses. Many goods have several uses, some more important than others. Electricity at a high price is used for lighting only; at a low price it is also used for heating water and running an air conditioner. As price falls, the good is put to its less urgent uses as well.

The assumptions: the part students omit

The law holds other things being equal. Six things are being held constant, and naming them is worth marks because each of them, when it changes, shifts the whole curve.

1. The income of the buyer does not change.
2. The tastes and preferences of the buyer do not change.
3. The prices of related goods, substitutes and complements, do not change.
4. The number of buyers in the market does not change.
5. Expectations about future prices do not change.
6. The good does not change in nature, and there is no change in the distribution of income or in the season.

A statement of the law without its assumptions is not a shorter answer, it is a wrong one, because as soon as any of the six moves, price and quantity can perfectly well rise together and the law is not contradicted at all.

Movement along the curve against a shift of the curve

This is the single most examined distinction in the topic and the most commonly muddled.

A movement ALONG the demand curve is caused by a change in the price of the good itself, with all six assumptions holding. It has two names.

• Extension of demand: price falls, quantity demanded rises, and the point moves down the curve to the right.
• Contraction of demand: price rises, quantity demanded falls, and the point moves up the curve to the left.

A SHIFT of the whole demand curve is caused by a change in any factor other than the price of the good itself. It also has two names.

• Increase in demand: the curve shifts to the right, so that more is bought at every price. Caused by a rise in income for a normal good, a taste in the good's favour, a rise in the price of a substitute, a fall in the price of a complement, more buyers, or an expectation that prices will rise.
• Decrease in demand: the curve shifts to the left, so that less is bought at every price.

A worked example: onions in Nashik and a change in the news

The market. At forty rupees a kilogram, Lasalgaon households buy 3,000 quintals a week.

Case one: the price falls to thirty rupees because the new crop has arrived. Households buy 4,200 quintals. This is an extension of demand and a movement down the curve. Nothing has shifted; the same schedule is being read at a different price.

Case two: at the same forty rupees, an announcement is made that exports will be permitted from next month and prices are expected to rise. Households now buy 3,900 quintals at forty rupees, stocking up. This is an increase in demand and a rightward shift of the whole curve, caused by expectations, one of the six things held constant in the law.

Why the distinction matters in practice. If a court or a regulator is asked whether a price rise "caused" a fall in consumption, the answer depends on which of the two happened. If demand shifted at the same time, the observed fall in quantity may understate or overstate the effect of price entirely. This is exactly why the law is stated with its assumptions.

The exceptions to the law of demand

There are situations in which a higher price is accompanied by a larger quantity bought. An examiner asks for them by name.

1. Giffen goods. Named after Sir Robert Giffen, who is said to have observed that when the price of bread rose, the poorest English families bought more of it. The explanation is that bread was so large a share of their budget that a rise in its price made them much poorer in real terms, and they responded by giving up meat, which was dearer per calorie, and eating still more bread. A Giffen good is a strongly inferior good that occupies a large share of a poor household's spending. It is the one genuine exception in theory, because the income effect works against the substitution effect and wins.

2. Veblen goods, or goods of ostentation. Named after Thorstein Veblen, who described conspicuous consumption. Diamonds, luxury watches and some designer goods are bought partly because they are expensive; a fall in price destroys the very quality that was wanted. Here the demand curve can slope upward over a range.

3. Expectation of a further price change. If buyers believe today's rise is the beginning of a much larger rise, they buy more today. This is not really an exception, because the assumption about expectations has been broken.

4. Ignorance of quality, or the price as a signal of quality. Where buyers cannot judge quality, they use price as a proxy and may buy more of the dearer article, believing it better. Common with medicines and with unfamiliar branded goods.

5. Necessities and habitual goods, in a limited sense. Salt, life saving medicine and, for an addicted consumer, tobacco or alcohol, are bought in nearly the same quantity whatever the price. Strictly this is very inelastic demand rather than an upward sloping curve, and a careful answer says so: the curve is steep, not reversed. The distinction is developed in [Elasticity of Demand].

6. Emergencies and speculation. In war, famine or a bank run, buying behaviour is not governed by the ordinary relationship.

A good answer distinguishes the two real exceptions, Giffen and Veblen, where the curve genuinely slopes upward, from the apparent ones, where an assumption has been broken or the curve is merely steep.

What beginners get wrong

"Demand means what people want." No. Without ability and willingness to pay there is no demand.

"The law says price and quantity always move in opposite directions in the real world." No. It says they do so if nothing else changes, and in the real world other things change constantly. Onion prices and onion sales can both rise in a year in which incomes rose faster.

"A rise in demand means a rise in the quantity demanded." These are different. A rise in demand is a shift of the curve; a rise in the quantity demanded is a movement along it caused by a lower price.

"Giffen goods are luxuries." The opposite. A Giffen good is an inferior staple bulking large in a poor household's budget. Veblen goods are the luxuries.

Limits and criticism

It is a qualitative law. It says the direction, not the size. How much quantity changes is the subject of the next chapter and is far more useful for policy.

The assumptions are heroic. Income, tastes and related prices do not stay still while a price moves.

It says nothing about time. The response to a price change is usually much smaller in a week than in a year, because habits and equipment take time to change. A rise in the petrol price changes driving a little at once and vehicle purchases a great deal later.

Aggregation hides diversity. A market demand curve adds a rich household's response to a poor household's, and a policy that relies on the average can miss both.

Quick revision

1. Demand is a want backed by ability and willingness to pay, at a stated price and for a stated period. Desire alone is not demand.
2. Law of demand: other things being equal, quantity demanded varies inversely with price. Fall in price extends demand; rise in price contracts it.
3. Five reasons for the downward slope: diminishing marginal utility, income effect, substitution effect, new buyers entering, and multiple uses of the good.
4. Six assumptions: unchanged income, tastes, prices of related goods, number of buyers, expectations, and nature of the good.
5. Movement along the curve, from the good's own price, is extension or contraction. Shift of the curve, from any other cause, is increase or decrease.
6. Real exceptions: Giffen goods (inferior staple, large budget share, income effect beats substitution effect) and Veblen goods (bought for their price). Apparent exceptions: expectations, price as a quality signal, necessities with very inelastic demand, and emergencies.
7. Market demand is individual demands added horizontally, quantity by quantity at each price.

Test yourself

1. State the law of demand and its assumptions. Other things being equal, the quantity demanded of a commodity varies inversely with its price: a fall in price extends demand and a rise contracts it. The assumptions held constant are the buyer's income, tastes and preferences, the prices of substitutes and complements, the number of buyers, expectations about future prices, and the nature of the good. Stated without those assumptions the law is not a shorter proposition but a false one.

2. Why does the demand curve slope downward? Give five reasons. Because of the law of diminishing marginal utility, so that each further unit is worth less and will only be bought at a lower price; the income effect, since a fall in price raises real income; the substitution effect, since the good becomes cheaper relative to substitutes; the entry of new buyers who were priced out at the higher price; and the extension of the good to less urgent uses as it becomes cheaper.

3. Distinguish an extension of demand from an increase in demand. An extension of demand is a movement down the same demand curve caused by a fall in the price of the good itself, with everything else unchanged. An increase in demand is a rightward shift of the whole curve caused by something other than the good's own price, such as a rise in income, so that a larger quantity is bought at every price including the original one. Confusing the two is the commonest error in this topic.

4. What is a Giffen good? Why is it a genuine exception? A Giffen good is a strongly inferior good that takes up a large part of a poor household's budget, such as a coarse staple grain. When its price rises, the household becomes so much poorer in real terms that it gives up the dearer foods it was also buying and consumes still more of the staple. The negative income effect outweighs the substitution effect, so quantity demanded rises with price and the curve slopes upward over that range. It is genuine because no assumption of the law has been broken.

5. Distinguish a Giffen good from a Veblen good. A Giffen good is an inferior necessity bought by poor households, and the upward slope arises from a powerful negative income effect. A Veblen good is a luxury bought partly because it is expensive, so the demand depends on the price being high and a fall in price reduces its attraction. The first is about poverty; the second is about display.

6. "Salt is an exception to the law of demand." Do you agree? Not strictly. The quantity of salt bought changes very little when its price changes, because it is a necessity that takes a tiny share of the budget and has no substitute. That makes its demand highly inelastic, so the curve is very steep, but it still slopes downward. An exception in the true sense requires an upward sloping curve, which salt does not have. The correct answer distinguishes a steep curve from a reversed one.

7. A market has two buyers. At 20 rupees A buys 5 units and B buys 3; at 15 rupees A buys 8 and B buys 6. Construct the market demand schedule and say what it illustrates. At 20 rupees the market demand is 8 units; at 15 rupees it is 14 units. The schedule is obtained by adding the quantities demanded at each price, which is horizontal summation, and never by adding the prices. It illustrates the law of demand, since the lower price is associated with the larger market quantity.

Ed = 1.5. Demand for these mangoes is elastic: a one per cent fall in price brings a one and a half per cent rise in quantity.

The five degrees of elasticity

An examiner asks for these by name, with the numerical value and the shape of the curve.

The two extreme cases are limiting cases used for teaching. Real goods lie between them, and most everyday goods sit somewhere between 0.2 and 3.

The four methods of measuring elasticity

MU can ask for these, and a complete answer names all four.

1. The percentage or proportionate method. The formula above. It is the standard method and the one to use unless a question specifies otherwise.

2. The total outlay or total expenditure method. Marshall's own method, and the most useful one to remember because it needs no arithmetic. Total outlay is price multiplied by quantity, which is also the seller's total revenue. Compare total outlay before and after the price change.

When price RISES the table reverses: outlay falling means elastic demand, outlay rising means inelastic demand.

Check it against the mango example. Before: 50 multiplied by 1,000 is 50,000 rupees. After: 40 multiplied by 1,300 is 52,000 rupees. Price fell and outlay rose, so demand is elastic. This agrees with the Ed of 1.5 calculated above, which is the point of running both methods on the same numbers.

3. The point method, also called the geometrical method. Elasticity at a single point on a straight line demand curve is measured by dividing the lower segment of the curve, below the point, by the upper segment, above the point. It follows that on a single straight line demand curve, elasticity is different at every point: greater than one on the upper half, exactly one at the midpoint, and less than one on the lower half. That is worth stating in an answer because it destroys the common belief that a straight demand curve has one elasticity.

4. The arc method. Between two points that are far apart, the percentage method gives a different answer depending on which point you start from. The arc method removes the ambiguity by using the averages of the two prices and the two quantities as the base:

Ed = (change in Q divided by the sum of the two quantities) divided by (change in P divided by the sum of the two prices), the factors of two cancelling.

Worked on the mangoes. Change in quantity 300, sum of quantities 2,300. Change in price 10, sum of prices 90. So 300/2300 is 0.1304 and 10/90 is 0.1111, giving Ed of 1.17. Note that this differs from the 1.5 found by the percentage method, and neither is wrong: the percentage method measures at a point and the arc method over a range.

What determines whether a good is elastic

Six determinants. An examiner asks for them and each carries an example.

1. The availability of close substitutes. The most important single determinant. The more and the closer the substitutes, the more elastic the demand, because buyers can switch. Demand for one brand of tea is elastic; demand for tea in general is much less so; demand for salt, which has no substitute, is nearly inelastic.

2. The nature of the good. Necessities have inelastic demand, because they must be bought whatever the price. Comforts are moderately elastic and luxuries are highly elastic.

3. The share of income spent on it. A good taking a tiny share of the budget, such as matchboxes or newspapers, has inelastic demand, because a doubling of its price is barely noticed. A good taking a large share, such as housing or a vehicle, has elastic demand.

4. The number of uses. A good with many uses, such as electricity or steel, has more elastic demand, because as its price falls it is put to further uses and as its price rises the least important uses are given up first.

5. Time. Demand is more elastic the longer the period allowed. A rise in the price of diesel changes little in a month and a great deal in five years, once vehicles and routes have been changed. Always add this if a question asks for determinants, because it is the one most often left out.

6. Habit and postponability. Goods of addiction or habit, such as tobacco, have inelastic demand. A purchase that can be postponed, such as repainting a house, has elastic demand.

A seventh point sometimes asked for is the existence of complementary goods: petrol's demand is tied to the stock of vehicles, which does not change quickly, and that ties down its elasticity in the short run.

A worked example: the tax that collects and the tax that reforms

The situation. The State of Maharashtra is considering two new levies of equal size: one on cigarettes and one on restaurant meals in a city where there are many restaurants.

Cigarettes. Demand is inelastic: habit, no close substitute, and a small share of most budgets. Suppose Ed is 0.4. A twenty per cent rise in price reduces quantity by eight per cent. The State collects a great deal of revenue and does relatively little to reduce smoking in the short run.

Restaurant meals. Demand is elastic: many substitutes including eating at home, the expenditure is postponable, and it takes a noticeable share of income. Suppose Ed is 2. A twenty per cent rise in price reduces quantity by forty per cent. The State collects much less than it hoped and the restaurants bear a large part of the burden through lost trade.

The two lessons a student should draw.

1. A revenue tax should be laid on inelastic goods; a discouraging tax works on elastic ones. Governments tax petrol, liquor and tobacco heavily for exactly this reason, and the fact that these are also goods policy wishes to discourage is a happy coincidence rather than the main motive.
2. Who actually bears a tax depends on elasticity. The more inelastic the demand relative to supply, the more of the tax the buyer pays; the more elastic the demand, the more the seller absorbs. This is called the incidence of a tax and it is taken up again in [The Sources of Public Revenue].

What beginners get wrong

"A steep curve is inelastic and a flat one elastic, always." Only when the two curves are drawn on the same axes and the same scale. Elasticity is not the slope; it is the slope multiplied by the ratio of price to quantity, which is why elasticity changes along a straight line.

"Elasticity is a property of the good." It is a property of the good at a price, in a market, over a period. Petrol is inelastic in a week and much more elastic over a decade.

"An elastic good is one people buy a lot of." No. It is one whose quantity responds sharply to price.

"Elasticity is negative, so the answer is minus 1.5." The ratio is negative and the convention is to quote the absolute value. Say once that the sign is dropped.

Limits and criticism

It assumes everything else is held constant, and inherits every assumption of the law of demand.

It is measured after the event. Elasticities are estimated from past data and can change when tastes, technology or the range of substitutes changes.

It varies along the curve, so a single number describes a range only approximately, which is why the arc method exists.

It says nothing about why. Two goods with the same elasticity can behave quite differently when a substitute appears.

Quick revision

1. Price elasticity of demand is the percentage change in quantity demanded divided by the percentage change in price. Introduced by Marshall, 1890. The sign is negative and by convention the absolute value is quoted.
2. Five degrees: perfectly elastic (infinity, horizontal), relatively elastic (greater than 1), unitary (equal to 1, rectangular hyperbola), relatively inelastic (less than 1), perfectly inelastic (zero, vertical).
3. Four methods: percentage, total outlay, point (lower segment divided by upper segment), and arc (using the sums of prices and quantities as the base).
4. Total outlay rule: when price falls, outlay rising means elastic, unchanged means unitary, falling means inelastic. Reverse it for a price rise.
5. Six determinants: substitutes, nature of the good, share of income, number of uses, time, and habit or postponability.
6. On a straight line demand curve elasticity is greater than one on the upper half, one at the midpoint and less than one on the lower half.
7. Tax rule: revenue is raised on inelastic goods, behaviour is changed on elastic ones, and the more inelastic the demand the more of the tax the buyer bears.

Test yourself

1. Define price elasticity of demand and give the formula. It is the degree of responsiveness of the quantity demanded of a commodity to a change in its price. Ed equals the percentage change in quantity demanded divided by the percentage change in price, which can be written as the change in quantity divided by the change in price, multiplied by the original price divided by the original quantity. The ratio is negative and is conventionally quoted as a positive figure.

2. At 20 rupees, 400 units are sold; at 16 rupees, 500 units are sold. Calculate elasticity by the percentage method and by the total outlay method. By the percentage method: quantity rises by 100 on a base of 400, which is 25 per cent; price falls by 4 on a base of 20, which is 20 per cent; elasticity is 25 divided by 20, that is 1.25, so demand is elastic. By the total outlay method: outlay was 20 multiplied by 400, that is 8,000, and becomes 16 multiplied by 500, that is 8,000. Outlay is unchanged, which indicates unitary elasticity. The two answers differ because the percentage method measures at the starting point while total outlay compares two positions across a wide range, and this is precisely why the arc method exists.

3. Name and explain the five degrees of elasticity with the numerical value of each. Perfectly elastic, elasticity infinite, where any rise in price reduces demand to nothing and the curve is horizontal. Relatively elastic, elasticity greater than one, where quantity changes proportionately more than price. Unitary elastic, elasticity exactly one, where the two change in the same proportion and total outlay is constant. Relatively inelastic, elasticity between zero and one, where quantity changes proportionately less than price. Perfectly inelastic, elasticity zero, where quantity is unaffected by price and the curve is vertical.

4. State six determinants of elasticity of demand. The availability and closeness of substitutes; whether the good is a necessity, a comfort or a luxury; the proportion of income spent on it; the number of uses to which it can be put; the period of time allowed for adjustment; and habit or the extent to which the purchase can be postponed.

5. "Elasticity is the same as the slope of the demand curve." Is this correct? No. Slope is the ratio of the change in price to the change in quantity in absolute units, while elasticity is a ratio of percentage changes and therefore depends on the point at which it is measured as well as on the slope. On a straight line demand curve the slope is constant but elasticity falls continuously from infinity at the price axis to zero at the quantity axis, passing through unity at the midpoint. Comparison of steepness is only reliable when two curves are drawn on the same axes and scale.

6. A government wishes to raise revenue from a new indirect tax. Which goods should it choose, and why? Goods with inelastic demand, such as fuel, tobacco and liquor, because a rise in price reduces quantity only slightly, so the tax base survives and collections rise. A tax on elastic goods produces a large fall in quantity and disappointing revenue, and it falls heavily on the seller through lost sales. The same reasoning in reverse explains why a tax intended to discourage consumption rather than to collect revenue works better on goods with elastic demand.

7. Explain the total outlay method and apply it: a shopkeeper raises the price of an umbrella and finds his takings from umbrellas have fallen. The total outlay method compares the buyer's total spending, which is the seller's revenue, before and after the price change. When the price rises, a fall in total outlay indicates elastic demand, an unchanged outlay indicates unitary elasticity, and a rise in outlay indicates inelastic demand. Here the price rose and takings fell, so the demand for umbrellas at that shop is elastic, which is what one would expect where buyers can go to another shop or postpone the purchase.

Worked calculation. The price of tea rises by 20 per cent. The quantity of coffee bought rises by 8 per cent. Ec is 8 divided by 20, that is positive 0.4.

What the sign tells you. Here the sign is the whole point and must not be dropped.

The size tells you how close the relationship is. A cross elasticity of 4 between two brands of the same soap means they are near perfect substitutes. A cross elasticity of 0.1 between rail and air travel on a route means they barely compete.

Why competition authorities care. Defining the relevant market is the first step in every abuse of dominance case, and cross elasticity is the standard tool for it. If the cross elasticity between two products is high, they are in the same market and neither producer is dominant; if it is near zero, the market is narrower and a producer may be dominant within it. The Competition Act 2002 requires the Commission to determine the relevant product market, and section 19(7) lists the factors, which include physical characteristics, end use, consumer preferences and price. That is cross elasticity expressed in statutory language, and [Monopoly] returns to it.

The three elasticities compared

Elasticity of supply, in one paragraph

For completeness, because a question sometimes pairs them. Elasticity of supply is the percentage change in quantity supplied divided by the percentage change in price, and it is normally positive because supply curves slope upward. It is treated fully in [Supply and the Law of Supply].

What elasticity is actually for

This section answers the question "of what use is the concept of elasticity", which MU can set on its own. Eight uses, each with the reasoning rather than the assertion.

1. Pricing by a firm. A seller facing inelastic demand raises total revenue by raising the price; a seller facing elastic demand raises total revenue by lowering it. This is the total outlay rule of [Elasticity of Demand] read from the seller's side, and it is why a monopolist never prices in the inelastic range of its demand curve.

2. Taxation. Two separate points. A tax laid for revenue should fall on goods with inelastic demand, because the base survives the tax. And the incidence of any indirect tax, meaning who really bears it, is decided by the relative elasticities of demand and supply: the more inelastic side of the market bears the larger share. A tax on a good with perfectly inelastic demand is paid entirely by the buyer.

3. Price discrimination. A seller who can separate buyers into groups with different elasticities charges more to the group with the more inelastic demand. Railway fares by class, cinema tickets by time of day, and the different prices of the same medicine in different countries are all this. It is lawful in India only within limits; section 4(2)(a) of the Competition Act 2002 treats discriminatory pricing by a dominant enterprise as abuse.

4. Devaluation of a currency and the balance of payments. Devaluation makes exports cheaper abroad and imports dearer at home. It improves the trade balance only if the demands for exports and imports are sufficiently elastic. This is the Marshall Lerner condition, and it is the reason devaluation is not an automatic cure for a deficit. [Correcting a Disequilibrium] works it through with India's own experience.

5. Wage bargaining and the demand for labour. The demand for labour is a derived demand: it depends on the demand for what the labour makes. Where the demand for the product is inelastic and labour is a small part of total cost, a union can win a wage rise without much loss of jobs. Where the product's demand is elastic, the same demand costs jobs. Any argument about a minimum wage is at bottom an argument about these elasticities.

6. Public utility pricing and subsidy. A government supplying water, electricity or transport uses elasticity to decide how much of the cost can be recovered from the user and how much must be subsidised, and to predict how much consumption a tariff change will actually save.

7. Agricultural policy and the paradox of a good harvest. The demand for most foodgrains is inelastic. A bumper harvest therefore lowers the price by proportionately more than it raises the quantity, and the farmers' total revenue falls. A poor harvest can raise it. This is the paradox that makes minimum support prices and procurement necessary rather than merely generous, and [Government Measures to Raise Agricultural Productivity] takes it up.

8. Forecasting and planning. Income elasticity tells a planner which industries will grow fastest as national income rises. Goods with income elasticity above one, such as consumer durables, private transport and air travel, grow faster than the economy; goods with elasticity below one, such as foodgrains, grow more slowly. Every long term projection of demand for power, steel or housing rests on estimated income elasticities.

A worked example: the paradox of the good harvest

The facts. Growers in a district produce 10,000 quintals of onions a year and sell them at 40 rupees a kilogram. Rain is favourable and output rises 25 per cent to 12,500 quintals. The price elasticity of demand for onions is 0.5.

Step 1. Quantity has risen 25 per cent, and the whole crop must be sold. Step 2. With elasticity 0.5, a one per cent fall in price raises quantity demanded by half a per cent. To absorb 25 per cent more onions, the price must fall by 50 per cent. Step 3. The new price is 20 rupees. Step 4, the revenue. Before: 10,000 quintals at 40 rupees a kilogram. After: 12,500 quintals at 20 rupees. Quantity is up by a quarter and price is down by a half, so revenue falls to 62.5 per cent of what it was.

The conclusion. The growers have a larger crop and much smaller earnings. This is not a failure of the market; it is arithmetic, and it follows from inelastic demand. It is the standing economic justification for procurement at a support price, for buffer stocks, and for export permission in a glut year, all of which appear again in [Food Security: What It Means and How India Provides It].

What beginners get wrong

"A negative income elasticity means demand is falling." It means demand falls as income rises. Demand may be rising for other reasons.

"Inferior goods are bad goods." Inferior is a technical label about the response to income, nothing more.

"Cross elasticity is quoted without the sign, like price elasticity." No. In cross elasticity the sign is the answer, because it distinguishes a substitute from a complement.

"Elasticity is a fixed number for a good." It varies with price, with income level, with the period and with the availability of substitutes at the time.

Limits and criticism

Estimates come from the past and assume the relationships hold in future.

They assume other things constant, and in a real economy income, tastes and related prices all move together, which makes disentangling the three elasticities difficult.

Aggregate elasticities hide different households. The income elasticity of demand for milk is very different for a household near the poverty line and for one in the top decile, and a national average describes neither.

Quick revision

1. Income elasticity Ey equals percentage change in quantity divided by percentage change in income. Negative means inferior; zero neutral; between 0 and 1 a necessity; above 1 a luxury.
2. Engel's law: as income rises, the proportion of it spent on food falls, though the absolute amount rises. That is a positive income elasticity below one.
3. Cross elasticity Ec equals percentage change in quantity of X divided by percentage change in the price of Y. Positive means substitutes, negative means complements, near zero means unrelated. The sign is never dropped.
4. Uses: pricing, taxation and incidence, price discrimination, devaluation and the Marshall Lerner condition, wage bargaining, utility pricing, agricultural support, and forecasting.
5. The paradox of the good harvest: with inelastic demand, a larger crop reduces total farm revenue. It is the economic case for procurement and support prices.
6. Competition law uses cross elasticity to define the relevant product market, which is where a dominance inquiry begins.

Test yourself

1. Define income elasticity of demand and state how it classifies goods. It is the ratio of the percentage change in quantity demanded to the percentage change in the consumer's income, other things being equal. A negative value marks an inferior good, of which less is bought as income rises. A value of zero marks a neutral good. A positive value below one marks a necessity, since spending on it rises proportionately less than income. A value above one marks a luxury or superior good.

2. A family's income rises from 30,000 to 36,000 rupees and its purchase of butter rises from 2 kilograms to 3 kilograms a month. Calculate income elasticity and classify the good. Income rises by 6,000 on a base of 30,000, which is 20 per cent. Quantity rises by 1 on a base of 2, which is 50 per cent. Income elasticity is 50 divided by 20, that is 2.5. Since it exceeds one, butter is for this family a luxury or superior good.

3. Define cross elasticity and explain what its sign tells you. Cross elasticity of demand is the ratio of the percentage change in the quantity demanded of one good to the percentage change in the price of a related good. A positive value means the two are substitutes, because a rise in the price of one causes buyers to move to the other. A negative value means they are complements, used together, so a rise in the price of one reduces the quantity of both. A value at or near zero means the goods are unrelated.

4. State Engel's law and say what it implies for a growing economy. Engel's law states that as a household's income rises, the proportion of income spent on food falls, although the absolute amount spent may rise. It implies that as national income grows, the share of agriculture in total consumption expenditure declines and the shares of manufactured goods and services rise, which is one of the mechanisms behind the structural change of an economy from agriculture towards industry and services.

5. Explain four practical uses of elasticity. In pricing, because a firm facing inelastic demand raises revenue by raising price and a firm facing elastic demand by lowering it. In taxation, because a revenue tax should fall on inelastic goods and because the more inelastic side of a market bears more of the burden of an indirect tax. In devaluation, because a devaluation improves the trade balance only if the demands for exports and imports are sufficiently elastic. And in forecasting, because income elasticity indicates which industries will grow faster than national income. Price discrimination, wage bargaining and agricultural support policy are further uses.

6. Why do farmers sometimes earn less from a bigger crop? Because the demand for foodgrains and vegetables is inelastic. A larger crop can be sold only at a much lower price, since a given percentage fall in price increases the quantity demanded by a smaller percentage. If elasticity is 0.5, absorbing a 25 per cent larger crop requires a 50 per cent fall in price, so total revenue falls even though output rose. This is the economic justification for minimum support prices, procurement and buffer stocks.

7. How does cross elasticity help a competition authority? It measures whether two products compete. A high positive cross elasticity shows that buyers switch readily between them, so they belong to the same relevant product market and neither seller can behave independently of the other. A cross elasticity near zero shows that the products do not constrain each other, so the market is narrower and a seller within it may hold a dominant position. Since dominance under the Competition Act 2002 is assessed within a relevant market, and section 19(7) directs attention to characteristics, end use, consumer preferences and price, the statutory test is cross elasticity reasoning in legal form.

3. New firms enter. At a low price only the most efficient producers can cover their costs. As the price rises, higher cost producers find it worth entering, so market supply rises for a reason that has nothing to do with any existing firm producing more.

4. Existing stocks are released. Where a good is storable, a higher price persuades holders to bring stock out of storage, as with the onion trader above.

The assumptions

The law holds other things being equal, and seven things are held constant. Naming them earns marks, because each of them, when it moves, shifts the whole curve.

1. The technique of production does not change.
2. The prices of the factors of production, that is the costs of labour, raw material, power and capital, do not change.
3. The prices of other goods the producer could make do not change.
4. The number of sellers does not change.
5. The goal of the firm, normally profit maximisation, does not change.
6. Government policy, meaning taxes, subsidies and controls, does not change.
7. Expectations about future prices do not change.

Movement along the curve against a shift of the curve

The same distinction as in [Demand and the Law of Demand], and examined just as often.

A movement ALONG the supply curve is caused by a change in the price of the good itself.

• Extension of supply: price rises, quantity supplied rises, the point moves up the curve to the right.
• Contraction of supply: price falls, quantity supplied falls.

A SHIFT of the whole supply curve is caused by anything other than the good's own price.

• Increase in supply: the curve shifts to the right, so more is offered at every price. Caused by better technology, cheaper inputs, a fall in tax or a rise in subsidy, more sellers, a good monsoon in the case of a crop, or a fall in the price of an alternative product.
• Decrease in supply: the curve shifts to the left. Caused by dearer inputs, a new tax, a natural calamity, or a rise in the price of an alternative product that draws producers away.

Elasticity of supply

The formula. Es equals the percentage change in quantity supplied divided by the percentage change in price. It is normally positive, because the two move together.

Worked calculation. The price of pots rises from 80 to 100 rupees, a rise of 25 per cent. Ravi's supply rises from 25 to 30, a rise of 20 per cent. Es is 20 divided by 25, that is 0.8, so supply is inelastic.

The five degrees, which mirror those for demand: perfectly elastic (infinite, a horizontal line), relatively elastic (greater than one), unitary (equal to one, a straight line through the origin), relatively inelastic (less than one), and perfectly inelastic (zero, a vertical line).

A useful geometrical fact. Any straight line supply curve passing through the origin has unitary elasticity at every point, whatever its slope. One that cuts the price axis above the origin is elastic throughout; one that cuts the quantity axis is inelastic throughout.

What determines elasticity of supply. Five determinants.

1. Time. The most important. Marshall's three periods are examinable in their own right and are set out below.
2. The nature of the good. Perishables have inelastic supply because they cannot be stored; durable goods have more elastic supply.
3. The cost of production as output rises. If costs rise steeply with output, supply is inelastic.
4. Whether inputs can be obtained easily. Supply of a good needing a rare mineral or a scarce skill is inelastic.
5. The ease of entry into the industry. Where licences, capital requirements or land make entry hard, supply is inelastic. This connects directly to the barriers to entry in [Market Structure: The Four Forms].

Marshall's three time periods

Alfred Marshall's answer to how supply responds is that it depends entirely on how long you allow. This is one of the most examinable ideas in the topic.

The market period, or very short period. So short that output cannot be changed at all. Supply is the existing stock and the supply curve is vertical, that is perfectly inelastic. Price is determined almost entirely by demand. A day's arrival of fish at a market is the standard example, and the price collapses in the evening because the fish cannot be kept.

The short period. Long enough to vary the variable factors, labour, raw material and hours worked, but not the fixed plant. Supply is somewhat elastic. A factory can run a second shift but cannot build a second factory.

The long period. Long enough to change everything, including plant and the number of firms in the industry. Supply is highly elastic and cost of production dominates price.

Marshall's own image is that demand and supply are like the two blades of a pair of scissors: it is idle to ask which blade cuts the paper. But the shorter the period, the more the work is done by demand; the longer the period, the more by supply and cost.

The exceptions to the law of supply

1. Fixed supply. Some things cannot be produced at all: land in a city, an old master's painting, a rare antique. The supply curve is vertical whatever the price.

2. Perishables, and a distress sale. A seller of fish or milk at the end of the day will accept a falling price and sell more rather than less, because the alternative is a total loss.

3. The backward bending supply curve of labour. This is the one an examiner most likes. As the wage rate rises, a worker offers more hours, up to a point. Beyond that point the worker is rich enough that another hour of leisure is worth more than another hour's pay, and the hours offered fall as the wage rises further. The income effect overtakes the substitution effect, exactly as it does for a Giffen good in [Demand and the Law of Demand].

4. Expectation of a further rise. If sellers expect the price to go on rising, a rise today can cause them to hold stock back and supply less, which is hoarding. Strictly this breaks the assumption about expectations rather than the law itself.

5. Agricultural output in the short run. A farmer who has sown cannot change the crop when the price moves. Within a season the supply curve is close to vertical.

6. A subsistence or target income producer. A weaver who needs a fixed income each month will work fewer hours when the price of cloth rises, because the target is reached sooner. The same logic as the backward bending labour supply curve.

A worked example: the potter, the price and the season

The facts. Ravi supplies 25 pots a week at 80 rupees. Three things then happen in successive months.

Month one: the price rises to 100 rupees because a festival is coming. Ravi works longer hours and hires his nephew. He supplies 30 pots. This is an extension of supply, a movement up the curve, and it is only possible at all because the period is long enough to vary labour, which makes it a short period response in Marshall's sense.

Month two: the price of clay doubles, though the price of pots is still 100 rupees. Ravi now supplies only 22 pots at that price. The whole curve has shifted left. This is a decrease in supply, caused by an input price, one of the seven things the law holds constant.

Month three: the price is back at 80 rupees, but Ravi buys an electric wheel. He now supplies 34 pots at 80 rupees, more than he ever offered at 100 before. This is an increase in supply caused by a change in technique, and it is a long period response, because it required a change in his fixed equipment.

What the example shows. The same producer, the same product, and three completely different answers, depending on which variable moved and how much time was allowed. That is why every statement of the law of supply carries both its assumptions and its time period.

What beginners get wrong

"Supply means the total quantity available." That is stock. Supply is the part of the stock offered for sale at a stated price in a stated period.

"A rise in supply and a rise in the quantity supplied are the same." They are not. A rise in the quantity supplied is a movement up the curve caused by a higher price. A rise in supply is a rightward shift caused by something else.

"Supply always slopes upward." In the market period it is vertical, and for labour it can bend backwards.

"A subsidy raises the price." A subsidy shifts the supply curve to the right, which lowers the price and raises the quantity. A tax does the opposite.

Limits and criticism

It assumes profit maximisation. Producers in Indian agriculture and in small household industry often work to a target income or to custom, and the law does not describe them well.

It ignores the time it takes to respond. The cobweb pattern in agriculture, where farmers sow this year on the basis of last year's price and so produce a glut and then a shortage in alternate years, is a well known failure of the simple statement.

It assumes the seller can get inputs. Where power, credit or raw material is rationed, a higher price produces no extra output at all.

Quick revision

1. Supply is the quantity offered for sale at a given price in a given period. It is not stock.
2. Law of supply: other things being equal, quantity supplied varies directly with price. Rise in price extends supply, fall contracts it.
3. Four reasons for the upward slope: the profit motive, rising marginal cost from diminishing returns, entry of new firms, and release of stocks.
4. Seven assumptions: unchanged technique, factor prices, prices of other goods, number of sellers, firm's objective, government policy, and expectations.
5. Movement along is extension or contraction; a shift is increase or decrease.
6. Elasticity of supply equals percentage change in quantity supplied over percentage change in price. A straight line through the origin has unitary elasticity throughout.
7. Marshall's three periods: market period, supply fixed and vertical, demand decides price; short period, variable factors only; long period, everything variable and cost decides price.
8. Exceptions: fixed supply, perishables and distress sales, the backward bending labour supply curve, expectations and hoarding, agriculture within a season, and target income producers.

Test yourself

1. Define supply and distinguish it from stock. Supply is the quantity of a commodity that sellers are willing and able to offer for sale at a given price during a given period of time. Stock is the entire quantity in existence at a moment. A trader with 500 quintals in a godown who offers only 100 quintals at today's price has a stock of 500 and a supply of 100. Every statement of supply must therefore carry a price and a period.

2. State the law of supply and its assumptions. Other things being equal, the quantity supplied of a commodity varies directly with its price, so a rise in price extends supply and a fall contracts it. The assumptions are that the technique of production, the prices of the factors of production, the prices of other goods the producer could make, the number of sellers, the objective of the firm, government policy on taxes and subsidies, and expectations about future prices all remain unchanged.

3. Why does the supply curve slope upward? Because a higher price widens the margin over cost and makes further production worth the effort and risk; because marginal cost rises as output expands against a fixed plant, so a producer will supply another unit only at a price that covers it; because higher cost producers who could not cover their costs at the low price now enter the market; and because holders of stock release it when the price rises.

4. Explain Marshall's three time periods and their effect on price. In the market period, output cannot be altered at all, so supply is perfectly inelastic and vertical, and price is decided almost entirely by demand. In the short period the variable factors such as labour and materials can be altered but not the plant, so supply is moderately elastic and both demand and cost influence price. In the long period every factor including plant and the number of firms can change, so supply is highly elastic and price tends to equal the cost of production. Marshall compared demand and supply to the two blades of a pair of scissors, with the shorter period giving more work to demand and the longer period more to supply.

5. What is the backward bending supply curve of labour? It is the observation that as the wage rate rises, a worker at first offers more hours, because leisure has become more expensive relative to income. Beyond a certain wage the worker's income is high enough that further leisure is valued more than further earnings, so the hours offered fall as the wage rises. The income effect has overtaken the substitution effect, which is the same mechanism that produces a Giffen good on the demand side.

6. Distinguish an extension of supply from an increase in supply, with an example of each. An extension of supply is a movement up the same supply curve caused by a rise in the price of the good itself, everything else being unchanged, as when a potter makes more pots because the price of pots has risen. An increase in supply is a rightward shift of the whole curve caused by something other than the good's own price, so that more is offered at every price, as when a fall in the price of clay or the purchase of an electric wheel lets the same potter offer more at the old price.

7. A straight line supply curve passes through the origin. What is its elasticity, and does its steepness matter? Its elasticity is exactly one at every point, and the steepness makes no difference to that. This follows because at any point on such a line the ratio of price to quantity equals the slope, so the two cancel in the elasticity formula. A straight line supply curve that cuts the price axis above the origin is elastic throughout, and one that cuts the quantity axis is inelastic throughout.

The rule to remember. When demand moves, price and quantity move in the same direction. When supply moves, they move in opposite directions. If you remember nothing else about this chapter, remember that sentence, because it lets you answer a question you have not seen before.

When both curves move at once, one of the two results is certain and the other is ambiguous. If demand and supply both increase, quantity certainly rises and price may rise, fall or stay the same depending on which shift is larger. If demand increases and supply decreases, price certainly rises and quantity is ambiguous. A complete answer says which is determinate and which is not.

What a legal price control does

This is where a law student earns the chapter. A price fixed by law is a price that is not the equilibrium price, and the consequences follow mechanically.

A price ceiling is a legal maximum. It is imposed to protect buyers, and it binds only if it is set below the equilibrium price. In India the general power is in section 3 of the Essential Commodities Act 1955, which allows the Central Government to control the price at which an essential commodity may be bought or sold. Rent control statutes do the same for housing.

What follows from a binding ceiling, in order.

1. Excess demand, that is a shortage, because the quantity demanded at the low price exceeds the quantity supplied.
2. Rationing by something other than price: queues, quotas, permits, ration cards, or a seller's personal preference for one buyer over another.
3. A black market, in which the good is sold above the legal price to those willing to pay, because the excess demand does not disappear when it is made unlawful.
4. Deterioration of quality, since the seller cannot compete on price and has no reason to compete on anything else.
5. A fall in supply over time, because the return to producing the good has fallen.

None of this shows that price control is wrong. A ceiling on the price of a life saving drug during an epidemic distributes a scarce good more equally than an auction would, and that is a decision about equity, not efficiency, of the kind [Why a Law Student Studies Economics] describes. What the economics shows is that a ceiling must be accompanied by a rationing mechanism and by a plan for supply, or the shortage will do the rationing on its own and do it worse.

A price floor is a legal minimum. It is imposed to protect sellers, and it binds only if it is set above the equilibrium price. A minimum support price for a crop and a statutory minimum wage are the two examples every Indian student needs.

What follows from a binding floor.

1. Excess supply, that is a surplus. In the crop case, unsold grain; in the labour case, unemployment among the workers whose output is worth less than the minimum.
2. A need for the State to buy the surplus if the floor is to be maintained, which is exactly what procurement at the minimum support price does, and why India holds buffer stocks. [Food Security: What It Means and How India Provides It] follows this through.
3. Storage and disposal costs, and eventually the question of what to do with grain that has been bought and cannot be sold at the floor price.

A worked example: an onion price ceiling

The facts. Onions in a city market are in equilibrium at 60 rupees a kilogram, with 400 quintals a day bought and sold. After public complaint, the State fixes a maximum price of 35 rupees under an order made in exercise of the power in section 3 of the Essential Commodities Act 1955.

Step 1, is the ceiling binding? Yes. 35 is below the equilibrium of 60, so it will have effects. A ceiling of 80 would have had none.

Step 2, what happens on the demand side. At 35 rupees households want far more onions than at 60. Suppose the quantity demanded is 640 quintals.

Step 3, what happens on the supply side. Traders will not bring the same quantity to a market where they must sell at 35. Suppose 300 quintals arrive.

Step 4, the shortage. 640 wanted, 300 available: a shortage of 340 quintals a day. Shops sell out by mid morning.

Step 5, how the 300 quintals are actually distributed. Not by price, because price is fixed. By queueing, by limits of one kilogram a household, by preference for regular customers, and by sale at a higher price to those who ask quietly.

Step 6, the second round. Traders divert onions to the neighbouring district where the order does not apply, or hold them, or sell them for processing. Arrivals fall further.

What a lawyer should take from it. The order achieves its stated object, a low legal price, and fails its real object, which was that households should be able to buy onions cheaply. Making the black market an offence does not close the gap between 640 and 300; only more onions, or a rationing rule the State itself administers, will do that. A well drafted control therefore comes with a distribution mechanism, which is precisely what the public distribution system is.

What beginners get wrong

"A price ceiling reduces the price paid." It reduces the legal price. The effective price, once queueing time and black market premiums are counted, can be higher for many buyers than the free price was.

"Equilibrium is a fair price." It is a clearing price. It carries no claim to fairness, and where incomes are very unequal the market clears at a price many households cannot pay.

"A ceiling above the market price protects buyers." It does nothing at all. Only a ceiling below equilibrium binds. The same in reverse for a floor.

"If demand and supply both rise, price rises." Not necessarily. Quantity certainly rises; price depends on which shift is larger.

Limits of the analysis

It assumes a competitive market. Where one seller sets the price, the analysis of [Monopoly] applies instead.

It assumes buyers and sellers are informed and can move freely, which is not true where information is poor and transport is costly, as in many rural markets.

It says nothing about how long adjustment takes. In agriculture the response is delayed by a whole season, which produces the alternating glut and shortage known as the cobweb.

It ignores distribution. Two markets can clear at the same price with completely different consequences for who eats.

Quick revision

1. Equilibrium price is where quantity demanded equals quantity supplied. Below it there is excess demand and price rises; above it there is excess supply and price falls.
2. The four shift cases: demand up, price and quantity up; demand down, both down; supply up, price down and quantity up; supply down, price up and quantity down.
3. The rule: demand shifts move price and quantity the same way; supply shifts move them opposite ways.
4. Both curves moving: one result is certain and the other is ambiguous, and the answer must say which.
5. A price ceiling binds only below equilibrium and produces shortage, non price rationing, black markets, falling quality and falling supply. Section 3 of the Essential Commodities Act 1955 is the Indian statutory power.
6. A price floor binds only above equilibrium and produces surplus, which somebody must buy. Minimum support price plus procurement is the standard Indian example; a minimum wage is the labour example.

Test yourself

1. Define equilibrium price and explain why the market returns to it. Equilibrium price is the price at which the quantity demanded equals the quantity supplied, so that there is no excess on either side and no tendency for price to change. Below it, excess demand causes buyers to bid against each other and sellers to raise their asking price, which contracts demand and extends supply until the gap closes. Above it, unsold stock accumulates and sellers cut prices, which extends demand and contracts supply. Both movements are self correcting, which makes the equilibrium stable.

2. What happens to equilibrium price and quantity if (a) demand increases, (b) supply increases, (c) both increase? If demand increases, both price and quantity rise. If supply increases, price falls and quantity rises. If both increase, quantity certainly rises but the effect on price is ambiguous and depends on which shift is larger: a larger increase in demand raises price, a larger increase in supply lowers it, and equal shifts leave it unchanged.

3. What is a price ceiling? State four consequences of a binding one. A price ceiling is a legal maximum price, imposed to protect buyers, and it has effects only if it is fixed below the equilibrium price. Its consequences are a shortage, since more is demanded than supplied at the controlled price; rationing by non price devices such as queues, quotas and personal preference; the appearance of a black market at a price above the legal one; and, over time, a decline in quality and in the quantity supplied because the return to producing the good has fallen.

4. What is a price floor, and what must accompany it? A price floor is a legal minimum price, imposed to protect sellers, and it binds only if it is fixed above the equilibrium price. It produces a surplus, because more is offered than is bought at that price. It can therefore be maintained only if somebody buys and holds the surplus, which in India is done by procurement at the minimum support price and by the holding of buffer stocks, with the storage and disposal costs that follow.

5. Onions are in equilibrium at 60 rupees. The State fixes a maximum of 80 rupees. What happens? Nothing. The ceiling is above the equilibrium price and therefore does not bind: the market already clears at 60, which is lawful. A ceiling has effects only when it is set below the price at which the market would otherwise clear. The same point in reverse applies to a floor set below equilibrium.

6. "The equilibrium price is the just price." Comment. It is not. Equilibrium means only that the market clears, so that everybody who is willing and able to pay that price is served and everybody willing to supply at it finds a buyer. It carries no judgment about fairness and takes the existing distribution of income as given, so where incomes are very unequal the clearing price for a necessity may be one that many households cannot pay. Whether that outcome is acceptable is a normative question of the kind separated out in [Positive and Normative Economics], and it is why legislatures intervene in the markets for food, housing, medicines and labour.

4. The firm's control over price. Whether the individual seller has to accept the market price or can set it. The word for a firm that must accept it is a price taker; for one that can set it, a price maker.

5. Knowledge. Whether buyers and sellers know the prices and qualities available. Perfect knowledge means nobody can charge more than the going rate without losing every customer.

A sixth criterion is sometimes added: the presence of selling costs, meaning advertising, which is absent under perfect competition and heavy under monopolistic competition and oligopoly.

The four forms, and why there are four

The two ends of the range are theoretical. Perfect competition has so many sellers of an identical product that none has any influence on price at all. Monopoly has one seller and no substitute. Neither exists in a pure form in any real economy, and both exist as benchmarks: one is what competition would look like if it were complete, and the other is what its absence would look like.

Between them lie the two forms in which almost all real business is done. Monopolistic competition has many sellers of a product each of whom has made their version a little different from the others. Oligopoly has a few sellers, each large enough that what one does affects the others.

The middle two were the great addition of the 1930s, made independently by Edward Chamberlin in the United States, whose Theory of Monopolistic Competition appeared in 1933, and Joan Robinson in England, whose Economics of Imperfect Competition appeared the same year. Before them, textbooks had only the two extremes and could not describe an ordinary retail street.

The comparison table

This is the table the next four chapters fill in, and it is the highest yielding thing in this topic. An examiner who asks for the features of any one form is asking for one column of it.

Two words that must not be confused: firm and industry

A firm is a single producing unit under one management.

An industry is all the firms producing the same or closely similar goods.

Under perfect competition the distinction is sharp and useful: the industry's supply curve slopes upward while the individual firm's demand curve is horizontal. Under monopoly the two collapse into one, because the firm is the industry. Under monopolistic competition the word industry is replaced by Chamberlin's product group, because the products are not the same good, and that is why the boundary of a monopolistically competitive industry is always arguable.

Why market structure matters in law

Because dominance, not size, is what Indian law regulates. Section 4 of the Competition Act 2002 prohibits the abuse of a dominant position, and the explanation to that section defines dominance as a position of strength in the relevant market in India that enables an enterprise to operate independently of competitive forces, or to affect its competitors or consumers in its favour. That definition is a description of market structure, not of turnover.

Because the relevant market must be defined before anything else. Whether an enterprise is dominant depends entirely on how widely the market is drawn. A firm with the whole of the market for one brand of soft drink has no power at all if the market is soft drinks; it may have a great deal if the market is one flavour sold in one city.

Because different structures call for different remedies. A monopoly created by statute is corrected by amending the statute. A monopoly created by a patent is time limited by the patent law itself. An oligopoly that colludes is attacked under section 3(3), which presumes that price fixing, output limitation, market sharing and bid rigging have an appreciable adverse effect on competition. Monopolistic competition needs no competition remedy at all, but it does need consumer protection law, because its characteristic problem is misleading differentiation rather than high price.

A worked example: how wide is the market for a bus ride?

The facts. Konkan Coaches runs the only private overnight bus between two towns. A passenger association complains that its fares are excessive and that it is dominant.

If the relevant market is "overnight private bus services on this route", Konkan Coaches has all of it. Its market share is one hundred per cent.

If the relevant market is "overnight travel between the two towns", the railway, shared taxis and a second operator running a morning service are all in it, and the share falls sharply.

How the question is decided. By the statutory factors: are the alternatives interchangeable or substitutable by the consumer having regard to characteristics, price and intended use, under section 2(t)? Do passengers actually switch when the fare rises, which is cross elasticity? Section 19(7)(b) makes price a factor and section 19(7)(c) makes consumer preference one, and section 19(6) brings in transport costs and the geographic reach.

Why the answer matters so much. Everything else in the case follows from it. Draw the market narrowly and Konkan Coaches is a monopolist whose pricing is examinable under section 4. Draw it widely and it is one competitor among several in an oligopoly, and its fares are its own business unless it has agreed them with somebody else.

What beginners get wrong

"Market means a place." It means the set of buyers and sellers between whom a single price tends to rule.

"A monopolist can charge any price it likes." No. It can set the price, but the quantity it then sells is decided by the demand curve. A monopolist chooses a point on the demand curve, not a point in the air. [Monopoly] works this through.

"Perfect competition is the best market." It is a benchmark for efficiency, not a policy target, and it cannot exist where products genuinely differ or where production requires large fixed investment.

"A large market share means dominance." Under Indian law, dominance is the ability to act independently of competitive forces, and share is evidence of it rather than a definition of it. A firm with sixty per cent of a market with free entry may have no such ability.

Limits of the classification

Real markets are mixed. The market for cars in India is an oligopoly at the top and closer to monopolistic competition in the small car segment.

The boundary between the forms is not sharp. How few is a "few" sellers? The classification is a set of ideal types used to organise thinking, not a taxonomy of nature.

It is static. It describes a market at a moment and says little about how the structure came about or how technology will change it.

It ignores the buyer's side. A market with one buyer is a monopsony, and with a few buyers an oligopsony. Indian agricultural markets before reform were often described this way, with many farmers selling to few licensed traders, and the analysis of market power runs the same way with the sides reversed.

Quick revision

1. A market is the set of buyers and sellers of a good among whom one price tends to rule. Indian law splits it into the relevant product market, section 2(t), and the relevant geographic market, section 2(s).
2. Five classifying criteria: number of sellers, nature of the product, freedom of entry, control over price, and knowledge. Selling costs make a sixth.
3. Four forms: perfect competition, monopolistic competition, oligopoly, monopoly. The two extremes are benchmarks; the two middle forms describe real business.
4. Chamberlin and Joan Robinson, both 1933, added the middle forms.
5. Price taker accepts the market price, price maker sets it.
6. The firm's demand curve is horizontal under perfect competition, downward sloping and highly elastic under monopolistic competition, kinked under oligopoly, and downward sloping and less elastic under monopoly.
7. In law: section 4 of the Competition Act 2002 regulates the abuse of dominance, and dominance is defined by the ability to act independently of competitive forces within a relevant market, which is why defining the market comes first.
8. Monopsony is one buyer; oligopsony a few.

Test yourself

1. Define market structure and state the criteria by which markets are classified. Market structure means the organisational characteristics of a market which determine the nature of competition within it and the extent of an individual firm's control over price. The criteria are the number and relative size of sellers; whether the product is homogeneous or differentiated; the freedom with which firms may enter and leave; the degree of control the individual firm has over price; and the state of knowledge among buyers and sellers. Selling costs and the degree of interdependence between firms are often added.

2. Distinguish a price taker from a price maker. A price taker must accept the price ruling in the market and can sell as much as it wishes at that price but nothing at all above it, so its own demand curve is horizontal. This is the position of a firm under perfect competition. A price maker can choose its price, but only along its downward sloping demand curve, so a higher price is always bought at the cost of a smaller quantity. This is the position of a monopolist and, within a narrower range, of a firm under monopolistic competition.

3. Name the four forms of market and give one Indian example of each. Perfect competition, approached by agricultural produce sold in a regulated market and by trading in a listed share. Monopolistic competition, seen in toothpaste, restaurants, salons and coaching classes. Oligopoly, seen in telecom, cement, airlines and passenger cars. Monopoly, seen in long distance rail travel provided by Indian Railways and in a medicine during the life of its patent.

4. Why must the relevant market be defined before dominance can be assessed? Because dominance is a position of strength within a market, and how strong an enterprise appears depends entirely on how widely the market is drawn. Section 2(t) of the Competition Act 2002 defines the relevant product market by reference to interchangeability or substitutability, and section 19(7) lists the factors, including physical characteristics or end use, price, consumer preferences and the costs of switching. Draw the market narrowly and an enterprise may hold all of it; draw it to include the substitutes buyers actually use and its share may be small and its conduct unremarkable.

5. Distinguish a firm from an industry, and say where the distinction breaks down. A firm is a single producing unit under one management; an industry is the group of firms producing the same or closely similar products. The distinction is sharpest under perfect competition, where the industry's supply curve slopes upward while each firm faces a horizontal demand curve. It disappears under monopoly, where the single firm is the whole industry. Under monopolistic competition it becomes blurred, because the products are similar but not identical, which is why Chamberlin used the term product group instead of industry.

6. What are monopsony and oligopsony? Monopsony is a market with a single buyer, and oligopsony one with a few buyers, so that market power lies on the buying side rather than the selling side. A single large purchaser can force the price down in the same way that a monopolist forces it up. Agricultural markets in which many small farmers sell to a small number of licensed traders have often been described in these terms, and the analysis of the resulting price distortion runs exactly parallel to the analysis of monopoly with the two sides reversed.

5. Perfect mobility of the factors of production. Labour and capital can move freely between firms and between uses, so that resources flow to wherever the return is highest.

6. No transport cost. Included so that a single price can rule throughout the market. If transport costs differ, prices differ, and the market has broken into several.

7. No government interference. No price control, no quota, no tax that falls unevenly on some sellers.

8. Absence of selling costs. No advertising, because there is nothing to advertise: the product is identical and everybody already knows the price. This is a striking feature and an examiner likes it. Advertising exists only where products differ or knowledge is imperfect.

Pure competition against perfect competition. Some writers reserve the term pure competition for the first three features alone, a large number of sellers, a homogeneous product and free entry, and require the remaining conditions for perfect competition. Mentioning the distinction and attributing it to Chamberlin is worth a line.

The consequences that follow from the features

These are what the features are for, and a good answer derives them rather than listing them separately.

A single ruling price. Follows from homogeneity plus perfect knowledge. There cannot be two prices for the same thing in a market where everybody knows both.

The firm is a price taker. It can sell any quantity it likes at the ruling price and nothing at all above it.

The firm's demand curve is horizontal, that is perfectly elastic, at the ruling price. This is the single most examined proposition in the topic. Note the contrast: the industry's demand curve slopes downward in the ordinary way, because the industry as a whole faces all the buyers. Only the individual firm faces a horizontal line, because it is too small to matter.

Average revenue equals marginal revenue equals price. Average revenue is total revenue divided by output, which for a firm selling every unit at the same price is that price. Marginal revenue is the addition to total revenue from selling one more unit, which is again that price because the price does not have to be cut to sell more. So AR = MR = P, and the firm's demand curve, its average revenue curve and its marginal revenue curve are one and the same horizontal line. Under every other market form MR lies below AR, and that single difference generates most of what distinguishes monopoly.

How price and output are determined

The industry fixes the price. Total market demand and total market supply meet at the equilibrium price, exactly as in [How Demand and Supply Together Set a Price]. That price is then a datum for every firm.

The firm fixes only its output. It expands output so long as the revenue from one more unit exceeds the cost of one more unit. So it produces where marginal cost equals marginal revenue, which here means where marginal cost equals price.

A numerical illustration. Suppose the ruling price is 50 rupees and a firm's marginal cost is 30 rupees at 100 units, 50 rupees at 140 units and 70 rupees at 160 units. At 100 units another unit adds 50 in revenue and 30 in cost, so it should be made. At 160 units another unit adds 50 and costs 70, so it should not. The profit maximising output is 140 units, where marginal cost has risen to equal the price.

Short run and long run equilibrium

In the short run the number of firms is fixed and plant cannot be changed. A firm produces where price equals marginal cost, and at that output it may earn:

• supernormal profit, if price is above average total cost;
• normal profit, if price equals average total cost. Normal profit is the minimum return needed to keep the entrepreneur in this line of business, and in economics it is counted as a cost, not as profit;
• a loss, if price is below average total cost. A firm continues to produce at a loss in the short run so long as price covers average variable cost, because it is then contributing something towards its fixed costs. Below average variable cost it shuts down. That price is called the shutdown point.

In the long run, entry and exit do their work. If firms are earning supernormal profit, new firms enter, industry supply rises, price falls, and profits are competed away. If firms are making losses, some leave, supply falls, price rises. The process stops only when price equals average cost and every firm earns exactly normal profit.

So in long run equilibrium under perfect competition, price equals marginal cost equals the minimum of average cost, and only normal profit is earned. That single line is the most quoted conclusion in the whole of microeconomics, and its three parts each carry a meaning:

• Price equals marginal cost means the value buyers put on the last unit equals what it cost society to make it, so no reallocation could improve matters. This is allocative efficiency.
• Production at the minimum of average cost means each firm is producing at the lowest cost per unit it is capable of. This is productive efficiency.
• Only normal profit means no producer is extracting a surplus from buyers.

A worked example: the mandi at Lasalgaon

The market. Several thousand onion growers bring produce to the same regulated market on the same morning. The onions of any one grower are indistinguishable from any other's of the same grade.

Feature by feature. Very many sellers: yes. Homogeneous product within a grade: nearly. Free entry: largely, though land is a constraint. Knowledge: much better than it was, because arrivals and rates are published and reach growers by phone. No selling costs: correct, because a grower does not advertise onions. Transport costs: not zero, which is the first real departure.

The consequence. Sanjay, who brings forty quintals, cannot ask more than the ruling rate: the trader will simply buy from the next heap. Nor need he accept less. He is a price taker with a horizontal demand curve, and his only decision is how much to bring and when.

Where the model breaks, honestly stated. The buyers are not numerous. A limited number of licensed traders buy from many growers, which is the oligopsony noted in [Market Structure: The Four Forms]. The market is therefore competitive on the selling side and concentrated on the buying side, which is exactly why agricultural market reform in India has been about widening the set of permitted buyers rather than about the number of farmers.

What beginners get wrong

"The firm's demand curve is horizontal, so demand is unlimited." No. It means the firm can sell as much as it can produce at the going price, which is a statement about the firm's insignificance, not about the market's appetite.

"Perfect competition means there is a lot of competition." In a sense the opposite: no firm competes with any other by price, quality or advertising, because none of those is available. Rivalry in the ordinary sense is a feature of monopolistic competition and oligopoly.

"Normal profit means zero profit." Normal profit is a real return to the entrepreneur, counted as a cost of production. Zero economic profit and zero accounting profit are different things.

"A firm making a loss must shut down at once." In the short run it should continue if price covers average variable cost.

Limits and criticism

No market meets all eight conditions. Products are differentiated, knowledge is imperfect and entry is rarely free.

Homogeneity and product variety are in conflict. A world of perfect competition would offer consumers no choice of style, brand or quality at all, and consumers plainly value that choice.

It cannot accommodate economies of scale. Where average cost falls continuously with size, as in electricity transmission or railways, a large number of small firms is the most expensive way to produce, and competition destroys itself. That is the case of natural monopoly in [Monopoly].

It has no place for innovation. With perfect knowledge and homogeneous products, nobody can profit from being first. Schumpeter's criticism, taken further in [Why Trade Cycles Happen, and What Governments Do About Them], is that the temporary monopoly profit that perfect competition abolishes is precisely what pays for innovation.

It is static. It describes an equilibrium and not the process by which markets actually move.

Quick revision

1. Eight features: very many buyers and sellers; homogeneous product; free entry and exit; perfect knowledge; perfect factor mobility; no transport cost; no government interference; no selling costs.
2. Consequences: one ruling price; the firm is a price taker; the firm's demand curve is horizontal while the industry's slopes downward; and AR equals MR equals price.
3. Equilibrium of the firm: produce where marginal cost equals marginal revenue, which here means marginal cost equals price.
4. Short run: supernormal profit, normal profit or loss are all possible. Continue producing while price covers average variable cost; below that, shut down.
5. Long run: entry and exit remove supernormal profit and losses, so price equals marginal cost equals minimum average cost and only normal profit is earned.
6. Normal profit is a cost, being the minimum return that keeps the entrepreneur in the business.
7. Efficiency: price equals marginal cost gives allocative efficiency; production at minimum average cost gives productive efficiency. This is why the model is the benchmark.
8. Pure competition requires only many sellers, a homogeneous product and free entry; perfect competition adds the rest.

Test yourself

1. State the features of perfect competition. A very large number of buyers and sellers, each too small to influence price; a homogeneous product, so that buyers are indifferent between sellers; complete freedom of entry into and exit from the industry; perfect knowledge of prices and qualities on the part of all participants; perfect mobility of the factors of production; absence of transport costs, so that one price rules throughout; absence of government interference; and absence of selling costs, since there is nothing to advertise.

2. Why is the demand curve of a firm under perfect competition horizontal, while the industry's slopes downward? The individual firm is so small a part of the market that it can sell its entire output at the ruling price without depressing it, and it can sell nothing at all above that price because buyers know that identical goods are available elsewhere at the ruling rate. Its demand curve is therefore perfectly elastic at that price. The industry, by contrast, faces the whole body of buyers, and the market can absorb a larger total quantity only at a lower price, so the industry's demand curve obeys the ordinary law of demand.

3. Show why average revenue equals marginal revenue equals price under perfect competition. Average revenue is total revenue divided by the quantity sold, and since every unit is sold at the same ruling price, average revenue is that price. Marginal revenue is the addition to total revenue from selling one further unit; because the firm need not lower its price to sell more, that addition is again the full price. Hence average revenue, marginal revenue and price coincide, and the firm's demand, average revenue and marginal revenue curves are the same horizontal line. Under all other market forms marginal revenue lies below average revenue, because more can be sold only at a lower price on every unit.

4. Describe the long run equilibrium of a firm under perfect competition. Free entry and exit remove both supernormal profits and losses. If profits are being earned, new firms enter, industry supply rises and price falls; if losses are being made, firms leave, supply contracts and price rises. Equilibrium is reached only when price equals average cost, so that every firm earns exactly normal profit, and since the firm also produces where price equals marginal cost, the outcome is that price equals marginal cost equals the minimum point of average cost.

5. What is normal profit, and why is it treated as a cost? Normal profit is the minimum return that must be earned by the entrepreneur to keep them in that line of production rather than moving their capital and effort elsewhere. Because it is the payment necessary to retain a factor of production in its present use, it is counted as part of the cost of production. A firm earning only normal profit is therefore said to earn zero economic profit while remaining perfectly viable, which is why zero economic profit does not mean a business is failing.

6. Why is perfect competition regarded as efficient, and what does the model leave out? Because in long run equilibrium price equals marginal cost, so the value buyers place on the last unit equals its cost to society, which is allocative efficiency; and because each firm produces at the minimum of its average cost curve, which is productive efficiency. The model leaves out product variety, since homogeneity means no choice at all; economies of scale, since it cannot accommodate industries in which average cost falls continuously with size; and innovation, since perfect knowledge and free entry remove the temporary profit that rewards being first.

7. When should a perfectly competitive firm continue to produce at a loss? When price covers its average variable cost, even though it is below average total cost. In that situation the revenue pays all the variable costs and contributes something towards the fixed costs, which must be borne whether or not the firm produces, so producing reduces the loss. If price falls below average variable cost the firm loses more by producing than by stopping, and it should shut down. The price at which price just equals minimum average variable cost is called the shutdown point.

3. Control of a scarce input. Ownership of the only deposit of a mineral, or of the only spring.

4. Natural monopoly. Where the average cost of production falls continuously as output rises, because the fixed cost is very large and the additional cost of serving one more customer is small, one firm can always supply the whole market more cheaply than two can. Electricity distribution, water supply, gas pipelines and railway track are the standard examples. Competition here is not merely difficult, it is wasteful, which is why these industries are regulated rather than opened.

5. Amalgamation and combination. Firms merge or agree until one remains. This is why merger control exists: sections 5 and 6 of the Competition Act 2002 require combinations above prescribed thresholds to be notified to and approved by the Competition Commission.

6. Superior efficiency or a first mover advantage, sometimes reinforced by network effects, where a service becomes more useful to each user as more people use it.

How the monopolist fixes price and output

The rule is the same as for any firm: produce where marginal cost equals marginal revenue. What differs is that marginal revenue is not the price.

A worked schedule. A monopolist's demand and cost schedule.

Reading the table. Marginal revenue falls faster than price, exactly as feature 5 says: at three units the price is 80 but the third unit added only 60 to revenue. Profit is greatest at three units, and that is also where marginal revenue, 60, is closest to marginal cost, 50, before marginal cost overtakes it. At four units marginal revenue is 40 and marginal cost is 60, so the fourth unit reduces profit.

Two conclusions to state in an answer.

1. The monopolist charges a price above marginal cost. Here the price is 80 and the marginal cost of the third unit is 50. Under perfect competition price equals marginal cost. The gap is the measure of monopoly power.
2. The monopolist never produces in the inelastic range of its demand curve. Where demand is inelastic, marginal revenue is negative, and no firm adds output that reduces total revenue while adding to cost. This connects the topic directly to [Elasticity of Demand].

A monopolist can make a loss. Being the only seller does not guarantee profit; if demand is too small to cover average cost at any price, the firm closes. A monopoly on a product nobody wants is worth nothing.

Price discrimination

The meaning. Charging different prices to different buyers for the same good, where the difference is not explained by a difference in cost.

The three conditions. All three must hold.

1. The seller must have some market power, otherwise buyers charged the higher price go elsewhere.
2. The markets must be separable, by geography, by time, by age, by the nature of the buyer, or by a device that sorts buyers.
3. Resale must be impossible or costly. If the low price buyers can resell to the high price buyers, the scheme collapses. This is why discrimination is easiest in services, which cannot be resold.

The three degrees, in the classification of A. C. Pigou.

• First degree, also called perfect discrimination: every buyer is charged the maximum they would pay. A doctor in a small town who quietly charges what each patient can afford approaches it.
• Second degree: prices vary by quantity or by block, as with a telephone tariff or a slab based electricity charge.
• Third degree: buyers are sorted into groups with different elasticities and each group is charged a different price. Railway classes, student concessions, off peak cinema tickets, and the differential pricing of the same medicine in different countries.

The rule. The group with the more inelastic demand is charged the higher price.

Is it always bad? No, and a good answer says so. Third degree discrimination can allow a service to be supplied to a poor group at a price that would never cover its share of fixed costs, financed by a rich group who pay more. Railway fares are the standing example. What Indian law regulates is not discrimination as such but discrimination by a dominant enterprise: section 4(2)(a)(i) and (ii) of the Competition Act 2002 make it an abuse for a dominant enterprise to impose unfair or discriminatory conditions or prices in purchase or sale, including a predatory price, with an explanation that a condition or price adopted to meet the competition is not caught.

What the law does about monopoly in India

The old regime. The Monopolies and Restrictive Trade Practices Act 1969 attacked size itself, requiring large undertakings to obtain approval before expanding. It fitted the licensing system described in [Industrial Policy Before 1991] and was dismantled with it. Section 66 of the Competition Act 2002 repealed it.

The present regime attacks conduct, not size. Three limbs.

• Section 3 prohibits agreements that cause an appreciable adverse effect on competition, and by section 3(2) such an agreement is void. Section 3(3) presumes that agreements between competitors which fix prices, limit production or supply, share markets or rig bids have such an effect. This limb belongs mainly to [Oligopoly].
• Section 4(1) provides that no enterprise or group shall abuse its dominant position, and section 4(2) lists the abuses: unfair or discriminatory conditions or prices including predatory prices; limiting production or technical development to the prejudice of consumers; denial of market access; tying, that is making a contract conditional on accepting unconnected supplementary obligations; and using dominance in one market to enter or protect another. The explanation defines a dominant position as a position of strength in the relevant market in India enabling the enterprise to operate independently of competitive forces or to affect its competitors, consumers or the relevant market in its favour.
• Sections 5 and 6 regulate combinations, so that a monopoly is not created by merger.

Section 19(4) lists the factors by which dominance is judged, and they are worth knowing because they are economics in statutory form: market share, size and resources of the enterprise, size and importance of competitors, economic power including commercial advantages, vertical integration, dependence of consumers, monopoly acquired as a result of a statute, entry barriers, countervailing buying power, market structure and size of market, and social obligations and costs.

Section 27 sets out what the Commission may order on finding a contravention: it may direct the enterprise to discontinue the conduct, impose a penalty, and direct that agreements be modified.

The key point for an exam. Dominance is not unlawful in India. Abuse of dominance is. A firm that gains the whole of a market by being better than everybody else has broken no law.

A worked example: the only cement plant in a district

The facts. Deccan Cement is the only cement manufacturer within 400 kilometres. Bringing cement from further away adds 18 per cent to the delivered cost. It charges builders in the district 420 rupees a bag where the price 500 kilometres away is 340.

Is it a monopolist? On the economics, it is the sole seller within a radius set by transport cost, and transport cost is the barrier that keeps others out. On the law, the question is the relevant geographic market, and section 19(6) of the Competition Act 2002 directs attention to transport costs and to adequate distribution facilities among other things. A district sized geographic market is arguable precisely because of the 18 per cent.

Is the price an abuse? Not by itself. A high price is evidence, not an offence. The inquiry under section 4(2)(a) is whether the price is unfair or discriminatory, and the usual comparators are the firm's own costs, its prices in other markets and the prices of comparable producers. If Deccan Cement also refuses to supply builders who buy any cement from outside the district, that is much more serious: it is denial of market access under section 4(2)(c) and probably an exclusionary condition under section 4(2)(a)(i).

What a remedy would look like. Under section 27 the Commission could direct the practice to stop and impose a penalty. What it cannot sensibly do is order a second plant into existence, which is why the durable answers to a natural or transport based monopoly are regulation of conduct and the reduction of the barrier itself, here by better roads and rail freight.

Monopoly against perfect competition

What beginners get wrong

"A monopolist charges the highest possible price." No. It charges the price that maximises profit, which is a point on the demand curve. Charging more sells less and can reduce profit.

"Monopoly means a large firm." It means a sole seller in a relevant market. A single chemist in a remote village is a monopolist; a very large company competing hard with three others is not.

"Monopoly is illegal in India." Being dominant is lawful. Abusing dominance is not. The MRTP Act, which did attack size, was repealed by section 66 of the Competition Act 2002.

"A monopolist always earns supernormal profit." Only if demand is large enough to cover average cost. Otherwise it makes a loss or shuts.

Limits, criticism and the case in favour

The case against monopoly. Price above marginal cost, so output is below the level buyers would have paid for, which is the deadweight loss; a transfer from consumers to the producer; no pressure to reduce costs, which Leibenstein called X inefficiency; and the possibility of resources being spent on defending the monopoly rather than on producing.

The case in favour, which a complete answer must give. Where average cost falls with size, one firm is genuinely cheaper than many, and forcing competition raises costs for everybody. Monopoly profit funds research, and Schumpeter argued that the prospect of temporary monopoly is the reward that drives innovation. A patent is exactly that argument in statutory form. And a regulated monopoly can be made to serve social objectives, such as universal supply at a uniform price, that a competitive market would not.

The Indian policy answer has therefore been neither to prohibit monopoly nor to ignore it, but to open industries where entry was artificially barred, which is the story of [The New Industrial Policy 1991], to regulate the ones that are natural monopolies through sectoral regulators, and to police conduct under the Competition Act 2002.

Quick revision

1. Monopoly: one seller, no close substitute, blocked entry. The firm is the industry.
2. Six sources: statute or licence, patents, control of an input, natural monopoly from falling average cost, amalgamation, and efficiency or network effects.
3. MR lies below AR because the price must be cut on every unit to sell one more. Equilibrium where MC equals MR, with price above marginal cost.
4. The monopolist never produces where demand is inelastic, because MR is negative there.
5. Price discrimination needs market power, separable markets and no resale. Pigou's three degrees. The more inelastic group pays more.
6. Indian law: MRTP Act 1969 attacked size and was repealed by section 66 of the Competition Act 2002. Section 4(1) prohibits abuse of dominance, section 4(2) lists the abuses, section 19(4) lists the factors for dominance, sections 5 and 6 control combinations, section 27 gives the remedies.
7. Dominance is lawful; abuse is not.
8. Against monopoly: high price, restricted output, deadweight loss, X inefficiency. For it: economies of scale in natural monopolies, funding of innovation, and the possibility of regulated universal service.

Test yourself

1. Define monopoly and state its features. Monopoly is a market structure with a single seller of a commodity for which there is no close substitute and into which entry by other firms is barred. Its features are the single seller, so that the firm is the industry; absence of a close substitute, which is what gives the seller power; barriers to entry, which allow the position to last; the firm's position as a price maker, though it can fix either price or quantity and not both; a downward sloping demand curve with marginal revenue lying below it; the possibility of price discrimination; and the possibility of supernormal profit persisting in the long run.

2. Why does marginal revenue lie below average revenue under monopoly? Because the monopolist faces the whole market demand curve and can sell an additional unit only by lowering the price, and the lower price must be given on every unit sold, not merely on the extra one. The addition to total revenue is therefore the price of the extra unit minus the loss on all the earlier units, which is less than the price. Under perfect competition the firm need not lower its price to sell more, so marginal revenue equals price.

3. How does a monopolist determine price and output? By producing the output at which marginal cost equals marginal revenue, and then charging the price which the demand curve shows buyers will pay for that output. Because marginal revenue is below price, the resulting price exceeds marginal cost, which is the essential difference from perfect competition. The monopolist will never choose an output in the inelastic range of its demand curve, since marginal revenue is negative there and a further unit would reduce total revenue while adding to cost.

4. What is price discrimination? State its conditions and its degrees. Price discrimination is the charging of different prices to different buyers for the same commodity where the difference does not correspond to a difference in cost. It requires that the seller have market power, that the markets be capable of separation, and that resale from the cheaper market to the dearer one be impossible or too costly. Pigou distinguished first degree discrimination, where each buyer is charged the maximum they will pay; second degree, where the price varies by quantity or block; and third degree, where buyers are grouped by elasticity and each group charged differently. The group with the more inelastic demand pays the higher price.

5. How does Indian law deal with monopoly today, and how did that change? Under the Monopolies and Restrictive Trade Practices Act 1969 the law attacked size itself, requiring large undertakings to seek approval before expanding. That Act was repealed by section 66 of the Competition Act 2002, which regulates conduct instead. Section 4(1) provides that no enterprise or group shall abuse its dominant position, section 4(2) lists the abuses, and the explanation defines dominance as a position of strength in the relevant market in India enabling the enterprise to operate independently of competitive forces or to affect its competitors, consumers or the market in its favour. Section 19(4) lists the factors relevant to dominance, sections 5 and 6 control combinations, and section 27 sets out the remedies. Dominance itself is lawful; only its abuse is prohibited.

6. What is a natural monopoly, and why is it not simply broken up? A natural monopoly exists where the average cost of supply falls continuously as output rises, because fixed costs are very large and the cost of serving an additional customer is small, so that one firm can always supply the whole market more cheaply than several can. Electricity distribution, piped water and railway track are examples. Duplicating the network would raise total costs and prices, so competition is wasteful rather than merely difficult, and the usual answer is regulation of price and of service obligations by a sectoral regulator rather than the introduction of rival suppliers.

7. "Monopoly is always against the public interest." Discuss. Not always. The case against is strong: price exceeds marginal cost so output is restricted below the level consumers would have paid for, producing a deadweight loss; there is a transfer from consumers to the producer; and the absence of competitive pressure permits inefficiency. But where average cost falls with scale, a single supplier is genuinely the cheapest arrangement; monopoly profit can finance research, which is the reasoning behind the grant of patents; and a regulated monopoly may be required to supply everybody at a uniform price, which a competitive market would not do. Indian policy reflects this by permitting dominance, prohibiting its abuse, and regulating natural monopolies rather than dismantling them.

5. Heavy selling costs. Advertising, display, packaging, sponsorship. Under perfect competition selling costs are zero, and under monopoly they are mostly institutional. Here they are central, because the whole task is to persuade buyers that this variety is not the same as that one. Chamberlin's point is that selling costs do not merely shift demand between sellers; they can also shift the demand curve for the whole group.

6. Non price competition is more important than price competition. Firms compete by improving the product, by advertising, by service and by packaging, rather than by cutting price, because a price cut is easily matched.

7. Imperfect knowledge. Buyers do not know all prices and cannot compare all qualities, which is precisely what makes differentiation work.

8. The group, not the industry. Because the products are not the same good, Chamberlin replaced the word industry with product group, meaning the collection of firms making closely related varieties. The boundary of a group is always to some extent arguable.

Price and output

In the short run the firm behaves exactly like a small monopolist. It faces its own downward sloping demand curve, marginal revenue lies below it, and it produces where marginal cost equals marginal revenue, charging what the demand curve will bear at that output. It may earn supernormal profit, normal profit or a loss.

In the long run entry does its work, but not in the way it does under perfect competition. New firms enter the group with their own varieties. Each entrant takes a slice of the existing firms' custom, so every existing firm's demand curve shifts left and becomes more elastic, because there are now more substitutes. Entry continues until supernormal profit has gone.

The long run result, and the single most examined proposition in the topic. Equilibrium is reached where the firm's demand curve is tangent to its average cost curve. At that point price equals average cost, so only normal profit is earned, exactly as under perfect competition. But because the demand curve slopes downward, it can only touch the average cost curve at a point where average cost is still falling, which is to the left of the minimum of the average cost curve.

Two consequences follow, and both are examinable.

• Excess capacity. The firm produces less than the output at which its average cost would be lowest. The difference between that output and the one actually produced is called excess capacity, and it is the standing charge against this market form. Every restaurant with empty tables, every salon with an idle chair and every coaching class with vacant seats is an instance.
• Price above marginal cost. As under monopoly, though by a smaller margin.

The relationship to the other three forms

The last row is the honest summary. Monopolistic competition costs the consumer something in price and gives them something in choice, and there is no way to have both.

A worked example: a street of coaching classes

The market. Eleven coaching classes for Semester I law subjects operate within a kilometre of a college in Mumbai.

Where the monopoly element is. Vidya Classes has a teacher whose lecture notes students copy from each other, a hall five minutes from the college and an evening batch. No other class has that combination. If Vidya raises its fee from 9,000 to 9,600 rupees, it loses some students but not all: a student who values that teacher, or who can only come in the evening, stays.

Where the competition element is. If Vidya raises its fee to 15,000, it loses nearly everybody, because ten close substitutes are a short walk away. That is what a highly elastic downward sloping demand curve means.

What the firms actually compete on. Not price, which clusters within a narrow band, but on the things that differentiate: a free demo lecture, printed notes, a test series, a photograph of last year's toppers, batch size, air conditioning, and the reputation of one teacher.

The long run. Vidya earns well in its first two years. Two former teachers open their own classes. Vidya's enrolment falls from 180 to 120, its demand curve has shifted left and become more elastic, and its fee no longer earns supernormal profit. It now runs a hall built for 200 with 120 students in it. That is excess capacity, and it is the normal state of this market rather than a failure of management.

What the law contributes. The characteristic abuse here is not a high price but a false difference: a claim of a success rate nobody can verify, or a photograph of a topper who never enrolled. That is why the answer to this market form is consumer protection law rather than competition law: the Consumer Protection Act 2019 makes a false or misleading representation about the standard or quality of goods or services an unfair trade practice, and that is the wrong this market characteristically produces. Competition law has little to say here, because no firm in the group is dominant.

What beginners get wrong

"Monopolistic competition means a few big firms." That is oligopoly. Here there are many firms, none of which watches any particular rival.

"Product differentiation means the products are really different." It means buyers believe they are different, whether or not a chemist could tell them apart. A branded and an unbranded paracetamol tablet may be chemically identical and are in different product varieties economically.

"Excess capacity means the firm is badly run." It is the predicted long run outcome of the model. Every firm in the group has it.

"Advertising is waste." Partly. It also conveys real information and finances media. A balanced answer says that informative advertising has value and that combative advertising, which merely moves customers between near identical products, largely does not.

Limits and criticism

The product group cannot be defined precisely. How close must a substitute be to be inside the group? Chamberlin never answered this satisfactorily and it remains the model's weakest joint.

It assumes firms ignore each other. In a group of eleven coaching classes on one street, they plainly do not.

The tangency result assumes identical cost and demand curves for every firm, which conflicts with the premise that the products differ.

The waste charge is contested. Excess capacity is a cost, but variety is a benefit that the perfectly competitive benchmark values at zero. Consumers who pay more for a differentiated product are revealing that they value the difference, and it is not obvious that an economist should overrule them.

Quick revision

1. Monopolistic competition: many sellers, differentiated but closely substitutable products, fairly free entry. Developed by Chamberlin and Joan Robinson, both in 1933.
2. Product differentiation may be real, imagined or in the conditions of sale. Its effect is to give each firm its own downward sloping but highly elastic demand curve.
3. Selling costs are central and non price competition matters more than price competition.
4. Chamberlin's product group replaces the word industry, because the products are not the same good.
5. Short run: behaves like a small monopolist, MC equals MR, profit or loss possible.
6. Long run: entry drives the demand curve left and makes it more elastic until it is tangent to the average cost curve. Only normal profit is earned, at an output below minimum average cost.
7. Excess capacity is the difference between the least cost output and the output actually produced, and it is the standing criticism of this form.
8. The consumer's trade off: a higher price than perfect competition would give, in return for variety.
9. The legal answer to this market is consumer protection law rather than competition law, because the characteristic wrong is a false claim of difference rather than a high price, and no firm in the group is dominant.

Test yourself

1. Define monopolistic competition and state its features. It is a market structure in which a large number of sellers offer differentiated but closely substitutable products, with relatively free entry and exit, so that each firm has limited control over the price of its own variety while facing close competition from the others. Its features are a large number of sellers acting independently; product differentiation, whether real, imagined or in the conditions of sale; a downward sloping but highly elastic demand curve for each firm; relatively free entry; heavy selling costs; the predominance of non price competition; imperfect knowledge; and the replacement of the concept of an industry by Chamberlin's product group.

2. What is product differentiation, and what is its economic significance? Product differentiation is the making of one seller's product distinguishable from another's, whether by real differences of quality and design, by brand, packaging and advertising, or by the conditions of sale such as location, credit and service. Its economic significance is that it converts a seller who would otherwise face a horizontal demand curve into one facing its own downward sloping curve, so that a modest rise in price loses some customers but not all of them, and the seller acquires a limited power over its own price.

3. Explain the long run equilibrium of a firm under monopolistic competition, and the idea of excess capacity. In the long run new firms enter the product group with their own varieties, so each existing firm's demand curve shifts to the left and becomes more elastic, and supernormal profit is competed away. Equilibrium occurs where the firm's demand curve is tangent to its average cost curve, so that price equals average cost and only normal profit is earned. Because the demand curve slopes downward, the point of tangency must lie on the falling portion of the average cost curve, to the left of its minimum. The firm therefore produces less than the output at which its cost per unit would be lowest, and the shortfall is called excess capacity.

4. Distinguish monopolistic competition from perfect competition and from monopoly. It differs from perfect competition in that products are differentiated rather than homogeneous, in that each firm has a downward sloping rather than a horizontal demand curve, in that selling costs are heavy rather than absent, and in that long run output falls short of the minimum cost output so that excess capacity persists. It differs from monopoly in that there are many sellers rather than one, that close substitutes exist so the demand curve is much more elastic, that entry is relatively free, and that supernormal profit cannot survive in the long run.

5. Why is advertising heavy under monopolistic competition and absent under perfect competition? Because under perfect competition the products are identical and knowledge is perfect, so there is nothing to tell buyers that they do not already know and no way for one seller's output to be preferred to another's. Under monopolistic competition the whole basis of the firm's limited market power is that buyers see its variety as distinct, and advertising both creates and sustains that perception. Chamberlin also pointed out that selling costs can expand the demand for the group as a whole and not merely redistribute it within the group.

6. "Excess capacity under monopolistic competition is social waste." Discuss. On one view it is: firms produce below the output at which average cost is lowest, so resources are used less efficiently than they would be under perfect competition, and combative advertising that merely moves customers between near identical products adds cost without adding output. On the other view the comparison is unfair, because the perfectly competitive benchmark offers no variety at all and values choice at zero, whereas consumers who pay a higher price for a differentiated product are showing that they value the difference. The balanced answer is that excess capacity is a real cost, that some advertising is informative and some is not, and that the loss must be weighed against a gain in variety that the benchmark model cannot measure.

The assumption about rivals' reactions. Each firm believes that:

• if it cuts its price, the rivals will match the cut at once, so as not to lose customers. It therefore gains very little extra sales.
• if it raises its price, the rivals will not follow, and will be glad to pick up its customers. It therefore loses a great deal of sales.

The consequence. The firm's demand curve has two segments meeting at the current price: elastic above the current price, because a rise loses many customers, and inelastic below it, because a cut gains few. That produces a kink at the prevailing price.

Why the price then stays put. A kink in the demand curve produces a vertical gap in the marginal revenue curve at the current output. Marginal cost can rise or fall within that gap without altering the point where marginal cost equals marginal revenue. So costs can change appreciably and the profit maximising price does not move. That is price rigidity, derived rather than asserted.

The honest criticism, which a full answer includes. The model explains why a price, once established, stays where it is. It does not explain how that price came to be established in the first place, and it does not describe industries in which prices move together frequently, as they do where a cartel or a price leader is at work.

Price leadership and other non collusive patterns

Where firms do not agree formally, several patterns appear.

Price leadership. One firm sets the price and the others follow. The leader may be dominant, the largest firm; barometric, the firm best at reading market conditions; or low cost, the firm that can sustain the lowest price.

Cartels. A formal or informal agreement among rival firms on price, output, market shares or bidding. This is the subject of the law below.

Tacit collusion or conscious parallelism. Firms behave alike without any agreement, simply by watching each other. This is the hardest case for a competition authority, because parallel behaviour is not by itself unlawful; the authority must show more than the fact that prices moved together.

What the law says about oligopoly in India

An oligopoly is not unlawful. Agreeing is.

Section 3(1) prohibits any agreement in respect of production, supply, distribution, storage, acquisition or control of goods or provision of services which causes or is likely to cause an appreciable adverse effect on competition within India. Section 3(2) makes such an agreement void.

Section 3(3) is the provision that matters most here. Any agreement between enterprises or persons engaged in identical or similar trade, including cartels, which:

• (a) directly or indirectly determines purchase or sale prices;
• (b) limits or controls production, supply, markets, technical development, investment or provision of services;
• (c) shares the market or source of production by allocating a geographical area, a type of goods or services, a number of customers or in any other similar way;
• (d) directly or indirectly results in bid rigging or collusive bidding,

shall be presumed to have an appreciable adverse effect on competition. The proviso saves an agreement made by way of a joint venture that increases efficiency. A further proviso added by Act 9 of 2023 extends the presumption to a person not in the same trade who participates or intends to participate in furthering such an agreement, which reaches a hub and spoke arrangement organised by a trade association or a common intermediary. The Explanation defines bid rigging as an agreement which has the effect of eliminating or reducing competition for bids or of adversely affecting or manipulating the bidding process.

Why the word presumed matters. For the four practices in section 3(3), the authority does not have to prove harm to competition. The harm is presumed and the burden shifts to the firms to displace it. For other agreements, including vertical ones under section 3(4), harm must be established by reference to the factors in section 19(3): barriers to new entrants, driving existing competitors out, foreclosure of competition, accrual of benefits to consumers, improvements in production or distribution, and promotion of technical, scientific and economic development.

Section 46, the leniency provision. The Commission may impose a lesser penalty on a producer, seller, distributor or trader who is a party to a cartel and makes a full and true disclosure of the alleged violations, where the disclosure is vital. This is the mechanism that actually breaks cartels, and the economics behind it is worth stating: a cartel is unstable because each member gains by cheating on it, and leniency turns that instability into an incentive to confess first.

A worked example: four cement companies and a tender

The facts. Four companies supply almost all the cement in a State. A public works department invites tenders for 40,000 tonnes. The four quote 4,780, 4,790, 4,795 and 4,800 rupees a tonne. The lowest wins. Over the previous two years each of the four has won roughly one quarter of the department's tenders, and in each case the other three quoted within one per cent of the winner.

What the economics says. In a genuinely competitive tender with four bidders of differing costs, quotes should scatter, and the same firm should tend to win where its costs are lowest. Quotes clustered within a fraction of a per cent, combined with a rotation of winners, is the pattern a cartel produces, because the members must decide whose turn it is and the losers must bid just above the winner to make the auction look real.

What the law says. The conduct falls squarely within section 3(3)(d), bid rigging, and within section 3(3)(c), market sharing by allocating a number of customers. Under section 3(3) it is presumed to have an appreciable adverse effect on competition, so the department does not have to prove that it paid more. The four companies must displace the presumption. Under section 3(2) any agreement between them is void.

What breaks it. Section 46. The first of the four to make a full and true disclosure may obtain a reduced penalty. Each of the four knows the others may go first, which is exactly the instability the provision is designed to exploit.

The lawyer's caution. Similar prices are not by themselves an agreement. In a market for an identical product with similar costs, prices should be similar; that is competition working. What makes this example different is the combination of near identical quotes with a rotation of winners over time, which competition does not produce.

The four forms compared, completed

What beginners get wrong

"Oligopoly means two or three firms." It means few enough for interdependence. An industry with eight firms of which four are large can behave as an oligopoly.

"An oligopoly is illegal." No. Having few sellers is a fact about an industry. Agreeing on price, output, markets or bids is the wrong, and section 3(3) presumes its effect.

"Parallel prices prove a cartel." They do not. In a market for an identical product, similar prices are what competition produces. Something more is needed: rotation of winners, unexplained simultaneous increases, evidence of contact, or prices that move together against costs that do not.

"The kinked demand curve explains oligopoly prices." It explains why an established price is sticky. It does not explain what the price is.

Limits and criticism

There is no single theory of oligopoly. Because the outcome depends on what each firm believes the others will do, the models multiply: Cournot on quantities, Bertrand on prices, Stackelberg on leadership, Sweezy on the kink, and modern game theory on all of it. An examiner who asks "why is there no determinate solution under oligopoly" wants exactly this answer.

Cartels are unstable. Each member gains by secretly selling more than its quota, and the temptation grows as the cartel price rises. Most cartels either collapse or are betrayed.

Oligopoly is not simply bad. Industries with heavy fixed costs and continuing research, such as telecommunications, aircraft and pharmaceuticals, cannot support a large number of small firms. Some concentration is the price of the scale and the research, and Schumpeter's argument in [Why Trade Cycles Happen, and What Governments Do About Them] is that this is where innovation actually happens.

Quick revision

1. Oligopoly: a few sellers, each large enough that its decisions affect the others. Two sellers is a duopoly.
2. Interdependence is the defining feature and the source of every analytical difficulty.
3. Pure oligopoly sells an identical product; differentiated oligopoly sells branded versions.
4. The kinked demand curve (Sweezy, 1939): rivals match a price cut but not a price rise, so the curve is elastic above the current price and inelastic below it, marginal revenue has a vertical gap, and the price is rigid against changes in cost.
5. Non collusive patterns: price leadership, whether dominant, barometric or low cost; and tacit collusion.
6. Law: section 3(1) prohibits agreements with an appreciable adverse effect on competition and section 3(2) makes them void. Section 3(3) presumes that effect for price fixing, output limitation, market sharing and bid rigging, cartels included. Section 19(3) lists the factors where no presumption applies. Section 46 allows a lesser penalty for a cartel member who discloses.
7. Oligopoly is lawful; agreeing is not. Parallel pricing alone does not prove an agreement.
8. No determinate solution exists, because the outcome depends on assumed reactions.

Test yourself

1. Define oligopoly and state its features. Oligopoly is a market structure in which a few sellers supply the whole or most of the output of an industry, each with a share large enough that its price and output decisions materially affect the others. Its features are the small number of sellers; mutual interdependence, which is the defining characteristic; a product that may be homogeneous or differentiated; significant barriers to entry, usually of scale or licence; price rigidity; heavy non price competition and advertising; an indeterminate demand curve; and a constant temptation to collude.

2. Explain the kinked demand curve and what it is used to prove. The kinked demand curve, associated with Sweezy in 1939, rests on the assumption that rivals will match a price cut but will not follow a price rise. The firm's demand curve is therefore relatively elastic above the prevailing price, because a rise loses many customers to rivals who hold their price, and relatively inelastic below it, because a cut is matched and brings little extra custom. The two segments meet in a kink at the prevailing price, which produces a vertical discontinuity in the marginal revenue curve. Marginal cost may move up or down within that gap without changing the profit maximising output, so the price remains unchanged despite changes in cost, which is the price rigidity the model is used to explain.

3. Why is there no single determinate theory of oligopoly? Because each firm's best decision depends on what it expects its rivals to do, and its rivals are reasoning in exactly the same way about it. The outcome therefore depends on the reaction pattern assumed, and different assumptions yield different results: Cournot assumed rivals hold output constant, Bertrand assumed they hold price constant, Stackelberg modelled a leader and a follower, and Sweezy assumed asymmetric reactions to rises and cuts. Modern treatment uses game theory, which formalises the interdependence rather than removing it.

4. What is a cartel, and how does Indian law treat one? A cartel is an agreement among rival enterprises to fix prices, limit output or supply, share markets or rig bids. Under section 3(1) of the Competition Act 2002 an agreement causing or likely to cause an appreciable adverse effect on competition is prohibited, and section 3(2) makes it void. Section 3(3) expressly includes cartels and presumes such an effect where the agreement fixes prices, limits production or supply, shares markets or results in bid rigging, so that the burden shifts to the parties. The proviso protects genuine efficiency enhancing joint ventures, and an amendment of 2023 extends the presumption to a participant who is not in the same trade but furthers the agreement.

5. What is bid rigging, and how would you recognise it from bidding data? Bid rigging is defined in the Explanation to section 3(3) as an agreement between enterprises engaged in identical or similar production or trading which has the effect of eliminating or reducing competition for bids or of adversely affecting or manipulating the process of bidding. The signs in the data are quotations clustered within a very narrow band where costs differ; a rotation of winners across tenders; consistent losing bids by firms that never win but always participate; identical arithmetical errors or formats; and sudden withdrawal of bidders in favour of one another. None is conclusive on its own, and the presumption operates only once an agreement is established.

6. Why is section 46 of the Competition Act 2002 effective against cartels? Because a cartel is inherently unstable. Each member can gain by secretly selling more than its allotted share at slightly below the agreed price, and the higher the cartel price the greater that temptation. Section 46 allows the Commission to impose a lesser penalty on a party who makes a full and true disclosure of the violations, provided the disclosure is vital. That converts the members' mutual distrust into a race to confess first, and it is the mechanism by which most cartels are actually detected, since direct evidence of the agreement is otherwise very hard to obtain.

7. "Similar prices prove collusion." Comment. They do not. Where several firms sell an identical product with similar costs and can observe each other's prices, competition itself drives prices towards one another, and a market in which prices differed widely for the same good would be the surprising one. Parallel behaviour therefore has to be distinguished from agreement. What supports an inference of agreement is a pattern competition does not produce: a rotation of successful bidders, simultaneous increases unrelated to any change in cost, quotes clustered far more tightly than the firms' costs differ, or evidence of communication between them.

A leakage, also called a withdrawal, is income received that is not spent on domestically produced output. It reduces the flow.

An injection is expenditure that does not come out of current household income. It adds to the flow.

In a two sector model with a capital market:

• Saving (S) is a leakage. Income earned but not spent.
• Investment (I) is an injection. Firms borrow the savings through banks and financial markets and spend them on plant, machinery and stocks.

The condition for the flow to stay at the same level is that injections equal leakages: I = S.

What happens when they are unequal, which is the examinable part.

• If saving exceeds investment, less is being spent than is being earned. Firms find goods unsold, cut production, and lay off workers. Income falls in the next round. This is a contraction, and it is the mechanism behind the paradox of thrift in [Microeconomics and Macroeconomics].
• If investment exceeds saving, more is being spent than earned. Firms find stocks running down, raise production and employ more. Income rises. If the economy is already at full capacity, prices rise instead.

The three sector flow: adding the government

What the government adds. Two of each.

• Leakage: taxes (T). Income taken out of the circulation.
• Injection: government expenditure (G). Spending on goods and services, and transfer payments such as pensions and subsidies, put back in.

The condition now becomes S + T = I + G.

What this shows about fiscal policy, and it is the reason Module III exists. If the government spends more than it takes in tax, G exceeds T and the government is injecting more than it withdraws. That is a fiscal deficit, and its effect on the circular flow is expansionary. If it taxes more than it spends, the effect is contractionary. Every argument about the size of the deficit in [Deficits, Public Debt and the FRBM Act] is an argument about this.

The four sector flow: adding the rest of the world

What foreign trade adds.

• Leakage: imports (M). Money paid out to producers abroad, so it leaves the domestic circulation.
• Injection: exports (X). Money paid in by buyers abroad.

The full condition: S + T + M = I + G + X.

Rearranged, this says (S minus I) plus (T minus G) equals (X minus M): the excess of private saving over investment plus the government's surplus equals the current account surplus. That identity is why a large fiscal deficit tends to appear as a current account deficit, and it is the bridge between Module III and Module IV. [The Structure of the Balance of Payments] is the same idea seen from the other end.

The financial sector, in one paragraph

Households do not hand their savings to firms directly. Banks, insurers, mutual funds and the capital market collect savings and lend them to firms and to the government. That machinery is the subject of [The Financial System: Two Markets, One Job]. In circular flow terms its job is to turn the leakage of saving back into the injection of investment, and a financial system that does that badly leaves the economy operating below capacity with savings sitting idle.

A worked example: a village with four sectors

The setting. A small town. Take one year and follow 1,000 rupees.

Round one. A garment firm pays Meena 1,000 rupees in wages. That is a factor payment: money flowing from firm to household.

Round two, the leakages. Meena pays 100 rupees in tax, that is T. She buys a mobile phone imported from abroad for 200 rupees, that is M. She puts 150 rupees into a bank deposit, that is S. Total leakage 450 rupees. She spends the remaining 550 rupees on local goods and services, which is consumption, C.

Round three, the injections. The bank lends her 150 rupees deposit to a local builder who buys cement with it, that is I. The government spends the 100 rupees of tax on a school teacher's salary, that is G. And a buyer in Dubai pays 200 rupees for garments the firm exports, that is X. Total injection 450 rupees.

The result. Leakages of 450 are exactly matched by injections of 450, so the flow continues at 1,000 rupees. Every rupee that left the circulation came back into it by another door.

Change one thing. Suppose the bank cannot find a borrower and the 150 rupees sits idle. Injections are now 300 against leakages of 450. Spending in the town falls by 150 rupees, the local shopkeeper sells less, orders less, and next year Meena's firm hires fewer hands. That is a recession in miniature, and it is caused by nobody behaving badly: everybody did the prudent thing.

What the circular flow shows

Five conclusions, and an examiner asks for these under "importance of the circular flow".

1. The three measures of national income must agree, because they are one flow measured at three points. This is the foundation of [Measuring National Income].
2. The economy is interdependent. No sector can be understood alone, which is the argument of [Microeconomics and Macroeconomics] again.
3. Leakages and injections explain fluctuation. Trade cycles, treated in [Trade Cycles and Their Phases], are the flow speeding up and slowing down.
4. It shows where policy acts. Fiscal policy works on T and G, monetary policy on the S to I link through the interest rate, and trade policy on X and M. Modules III and IV are the detail of that sentence.
5. It distinguishes a stock from a flow. National income is a flow, measured over a period. Wealth and capital are stocks, measured at a moment. Confusing them is a common and costly error.

What beginners get wrong

"Money going round means the economy is growing." No. A circular flow at a constant level is an economy standing still. Growth means the circle getting larger each year.

"Saving is always good for the economy." Saving is good for the saver. For the economy it is a leakage, and it does good only if it is turned back into investment.

"Transfer payments are part of national income." A pension or a subsidy is a transfer, not a payment for current production, so it is not counted in national income. It does enter the circular flow, because the recipient spends it.

"Imports reduce national income." Imports are subtracted in the expenditure method because they were never part of domestic production, not because they are harmful. The subtraction is arithmetic, not judgment.

Limits and criticism

It is a simplification. Real economies have many sectors, inventories, and time lags between earning and spending that the diagram cannot show.

It assumes the money keeps moving. Money hoarded in cash and not deposited is a leakage with no matching injection.

It says nothing about distribution. The same flow is consistent with a very equal and a very unequal society.

The identity is always true and therefore explains nothing by itself. That leakages equal injections in the national accounts is true by construction after the event. The interesting question is at what level of income they are equal, and that requires the theory of income determination, which lies beyond this syllabus.

Quick revision

1. Circular flow: production creates income, income is spent, expenditure buys production. Output equals income equals expenditure, because they are three views of one circulation.
2. The idea goes back to Quesnay's Tableau Economique, 1758, and took its modern form in national accounting after Keynes.
3. Two flows: a real flow of factor services and goods, and a money flow of factor payments and consumption expenditure, moving in opposite directions.
4. Two sector: households and firms. Three sector: add government. Four sector: add the rest of the world.
5. Leakages: saving, taxes, imports. Injections: investment, government spending, exports.
6. Equilibrium condition: S + T + M = I + G + X. In two sectors it reduces to S = I.
7. If leakages exceed injections income falls; if injections exceed leakages income rises, or prices do if capacity is full.
8. Policy acts on the flow: fiscal policy on T and G, monetary policy on the link from S to I, trade policy on X and M.

Test yourself

1. What is the circular flow of income? Describe the two sector model. It is the continuous movement of goods, services and money payments between the sectors of an economy, in which the income generated in production is spent on output and that expenditure becomes income again. In the two sector model households own the factors of production and supply them to firms, and firms use them to produce goods and services. There are two flows in opposite directions: a real flow of factor services from households to firms and of goods and services from firms to households, and a money flow of factor payments from firms to households and of consumption expenditure from households to firms. With no saving, government or foreign trade, output, income and expenditure are equal and the flow repeats at the same level.

2. Define leakage and injection, and list them for a four sector economy. A leakage is income received but not spent on domestically produced output, which reduces the flow; an injection is expenditure that does not arise out of current household income, which adds to it. In a four sector economy the leakages are saving, taxes and imports, and the injections are investment, government expenditure and exports. The flow remains at the same level when saving plus taxes plus imports equals investment plus government expenditure plus exports.

3. What happens if leakages exceed injections? Less is being spent than is being earned, so firms find their goods unsold and their stocks rising. They respond by cutting production and employment, so incomes fall in the following round and spending falls further. The economy contracts until leakages and injections are equal again at a lower level of income. The reverse case, injections exceeding leakages, raises output and employment if there is spare capacity, and raises prices if there is not.

4. Why must national output, national income and national expenditure be equal? Because they measure the same circulation at three different points. Whatever is produced is sold or added to stocks, and its value accrues as income to the factors that produced it, in the form of wages, rent, interest and profit. That income is either spent on output or saved, and saving reappears as investment expenditure. The value of production, the sum of factor incomes and the total of expenditure are therefore three views of one quantity, which is why the production, income and expenditure methods of measuring national income must give the same answer.

5. How does the circular flow explain the effect of a fiscal deficit? Taxes are a leakage from the flow and government expenditure is an injection into it. When the government spends more than it collects in tax, it is putting more into the circulation than it takes out, so total expenditure rises, and with spare capacity output and employment rise with it. When it collects more than it spends, the effect is contractionary. This is why the size of the deficit is treated as an instrument of demand management, and why its financing, whether by borrowing from the public or from the banking system, matters for the flow.

6. Distinguish a stock from a flow, with examples from this chapter. A flow is a quantity measured over a period of time, and a stock is a quantity measured at a point of time. National income, consumption, saving, investment and exports are flows and must always be stated with a period, such as a year. Wealth, the capital stock, money supply and foreign exchange reserves are stocks and are stated as at a date. Saving is a flow; the accumulated bank balance it produces is a stock.

Net factor income from abroad (NFIA) is the income Indian residents earn abroad, as wages, interest, rent and profit, minus the income foreigners earn in India. For India NFIA is normally negative, because the profits, interest and dividends flowing out to foreign owners of capital in India exceed the factor income Indian residents earn abroad. So India's GNP is normally a little smaller than its GDP.

A common confusion to name in an answer: remittances sent home by Indian workers abroad are not factor income if the worker is a resident of the foreign country; they are a transfer and appear in the current account of the balance of payments rather than in GNP. Only the earnings of Indian residents count as NFIA.

4. Net National Product (NNP). GNP minus depreciation.

NNP = GNP minus depreciation = NDP plus net factor income from abroad.

NNP at factor cost is what is properly called national income. When a textbook or an examiner says national income without qualification, this is what is meant.

5. Per Capita Income (PCI). National income divided by population.

PCI = National income divided by the population.

It is the standard measure for comparing living standards across countries and across time, and its weakness is that it is an average that says nothing about distribution. India's per capita income can rise in a year in which most households are worse off, if the gains go to a few.

6. Gross Value Added (GVA). The value of output minus the value of intermediate consumption, measured at basic prices. It is the contribution of an industry or a sector to output, before the taxes on products that buyers pay are added.

GVA at basic prices plus product taxes minus product subsidies = GDP at market prices.

Why India uses GVA, which is worth knowing. Since the base year revision of 2011-12, the Ministry of Statistics and Programme Implementation publishes GVA at basic prices by industry of origin as the production side headline, and GDP at market prices as the demand side headline. GVA is the better measure of what producers actually did, because it is not disturbed by a change in tax rates: a rise in the rate of tax on a product raises GDP at market prices without a single extra unit being made. The Economic Survey 2025-26 reports both, and for FY26 the First Advance Estimates of the Ministry of Statistics and Programme Implementation place real GDP growth at 7.4 per cent and real GVA growth at 7.3 per cent.

7. Green GDP. GDP adjusted for the depletion of natural resources and the cost of environmental degradation. It has a chapter of its own, [Green GDP and What GDP Leaves Out], because MU names it separately and because the reason it is hard to compute is itself examinable.

The relations, as a single ladder

This is the block an examiner most often asks to be reproduced, and it should be learned as a chain.

And along the other axis:

A worked chain with round numbers, so the arithmetic is visible.

Suppose for a year: GDP at market price 300 lakh crore; depreciation 30; net factor income from abroad minus 4; indirect taxes 40; subsidies 15; population 145 crore.

• NDP at market price = 300 minus 30 = 270
• NNP at market price = 270 plus (minus 4) = 266
• Net indirect taxes = 40 minus 15 = 25
• NNP at factor cost, national income = 266 minus 25 = 241 lakh crore
• Per capita income = 241 lakh crore divided by 145 crore people = about 1.66 lakh rupees a year

Three more distinctions that carry marks

Nominal against real. Nominal GDP, also called GDP at current prices, values output at the prices of the year being measured. Real GDP, or GDP at constant prices, values it at the prices of a fixed base year, which for India is 2011-12. Nominal GDP rises when prices rise even if nothing more is produced, so only real GDP measures growth. The ratio of the two, multiplied by 100, is the GDP deflator, a measure of the general price level covering the whole economy, unlike the consumer price index which covers a basket.

Market price against factor cost. The difference is net indirect taxes. A shirt selling for 800 with 100 of tax in it contributes 800 to GDP at market price and 700 to GDP at factor cost. Factor cost is what the factors of production actually received.

Domestic against national. Domestic is a boundary of territory. National is a boundary of residence. Toyota's Bengaluru plant is in India's GDP and not in its GNP to the extent the profit goes abroad; an Indian resident's earnings from a business in Dubai are in India's GNP and not in its GDP.

A worked example: Aisha's bakery and the boundary questions

The facts. Aisha runs a bakery in Pune. In a year she buys 12 lakh rupees of flour, sugar and fuel, pays 6 lakh in wages and 2 lakh in rent, spends 1 lakh on repairs to an oven that is wearing out, and sells bread for 26 lakh. She pays 2 lakh of goods and services tax on the sales.

Her gross value added. Output 26 lakh minus intermediate consumption 12 lakh equals 14 lakh rupees of gross value added. Note that the flour is not counted separately: it appears in the miller's value added, and counting it again here would be double counting.

Where the tax sits. If the 26 lakh includes 2 lakh of tax, then at basic prices her output is 24 lakh and her GVA at basic prices is 12 lakh. The 2 lakh appears in GDP at market prices as a product tax.

Net value added. 14 lakh gross minus 1 lakh of depreciation on the oven equals 13 lakh net value added.

How that 13 lakh is distributed. 6 lakh in wages, 2 lakh in rent, and the remainder as interest and Aisha's own profit. That is the income method seeing the same 13 lakh, which is the circular flow of the previous chapter in one small business.

The boundary questions.

• If Aisha is an Indian resident, all of it is in both GDP and GNP.
• If the bakery were owned by a company registered in Singapore, the value added would still be in India's GDP, because it was produced here, but the profit repatriated would be deducted in arriving at India's GNP.
• If Aisha bakes bread for her own family and does not sell it, it is not counted at all, because it is not marketed. That is the non monetised output problem of [The Difficulties of Measuring National Income in India].

What beginners get wrong

"GDP counts everything produced." It counts final goods and services produced for the market. Household work, subsistence output and the black economy are largely outside it.

"GNP is bigger than GDP." Not for India. India's net factor income from abroad is normally negative, so GNP is normally a little smaller than GDP.

"Rising GDP means people are better off." GDP can rise because of activity nobody wants: an epidemic raises medical spending; an accident raises repair spending; cutting a forest raises output and destroys an asset. That last point is the whole argument of [Green GDP and What GDP Leaves Out].

"National income means GDP." Strictly, national income is NNP at factor cost. In casual use GDP has taken over the phrase, but an examination answer should define it correctly.

"Transfer payments are income for national income purposes." A pension, a scholarship or an unemployment benefit is a transfer, not a payment for current production, and is excluded. So is the sale of a second hand good, which was counted in the year it was made, and so is a purely financial transaction such as buying a share.

Limits of these aggregates

They measure quantity, not welfare. A country can raise its GDP by producing more weapons and less food.

They ignore distribution. Per capita income is an average and can conceal deepening poverty.

They ignore what is not sold. Unpaid domestic work, overwhelmingly done by women, is a large part of real production in India and appears nowhere.

They ignore quality change. A phone today and a phone in 2011 are counted with the same rupee, though they are not the same thing.

They ignore leisure and environment. More output bought with longer hours and dirtier air is recorded as an unqualified gain.

Quick revision

1. The four choices that generate every aggregate: domestic or national; gross or net; market price, basic price or factor cost; total or per head.
2. GDP: final goods and services produced within the territory, before depreciation. NDP = GDP minus depreciation.
3. GNP = GDP plus net factor income from abroad. For India NFIA is normally negative, so GNP is a little below GDP.
4. NNP = GNP minus depreciation. NNP at factor cost IS national income.
5. PCI = national income divided by population.
6. GVA = output minus intermediate consumption, at basic prices. GDP at market price = GVA at basic prices plus product taxes minus product subsidies. India publishes GVA by industry of origin as the production side headline since the 2011-12 base revision.
7. Nominal against real: real is at constant prices, base year 2011-12 for India, and only real GDP measures growth. GDP deflator = nominal divided by real, times 100.
8. Excluded: transfer payments, second hand sales, purely financial transactions, and non marketed output.
9. India, FY26 First Advance Estimates: real GDP growth 7.4 per cent, real GVA growth 7.3 per cent, MoSPI, reported in the Economic Survey 2025-26.

Test yourself

1. Define GDP, GNP, NDP and NNP and state the relations between them. GDP is the money value of all final goods and services produced within the geographical boundary of a country during an accounting year, before deducting depreciation. GNP is the same measured for the residents of the country wherever they are, so GNP equals GDP plus net factor income from abroad. NDP is GDP minus depreciation, and NNP is GNP minus depreciation, which is also NDP plus net factor income from abroad. NNP at factor cost is what is properly meant by national income.

2. What is gross value added, and why does India publish it? Gross value added is the value of an industry's output minus the value of the intermediate goods and services it used up, measured at basic prices. GDP at market prices equals GVA at basic prices plus taxes on products minus subsidies on products. India has published GVA at basic prices by industry of origin as the production side headline since the base year revision to 2011-12, because GVA measures what producers actually did without being disturbed by changes in tax and subsidy rates, which can raise GDP at market prices without any change in output.

3. Distinguish nominal from real GDP and define the GDP deflator. Nominal GDP, or GDP at current prices, values the year's output at that year's prices, so it rises when prices rise even if output does not. Real GDP, or GDP at constant prices, values the same output at the prices of a fixed base year, which for India is 2011-12, so changes in it reflect changes in quantity alone. Only real GDP measures growth. The GDP deflator is nominal GDP divided by real GDP multiplied by one hundred, and it is a price index covering the whole economy rather than a fixed consumer basket.

4. Why is India's GNP usually smaller than its GDP? Because India's net factor income from abroad is normally negative. Foreign owners of capital operating in India earn more in profit, interest and dividends than Indian residents earn abroad in wages, rent, interest and profit, so the outflow exceeds the inflow. Since GNP equals GDP plus net factor income from abroad, a negative figure makes GNP a little smaller than GDP. Remittances from Indian workers settled abroad do not correct this, since a worker who is a resident of another country sends a transfer rather than factor income.

5. From the following, calculate national income and per capita income. GDP at market price 300; depreciation 30; net factor income from abroad minus 4; indirect taxes 40; subsidies 15; population 145 crore, all values in lakh crore rupees. NDP at market price is 300 minus 30, that is 270. NNP at market price is 270 plus minus 4, that is 266. Net indirect taxes are 40 minus 15, that is 25. National income, being NNP at factor cost, is 266 minus 25, that is 241 lakh crore rupees. Per capita income is 241 lakh crore divided by 145 crore, which is approximately 1.66 lakh rupees a year.

6. What is excluded from national income, and why? Transfer payments such as pensions, scholarships and subsidies to households, because they are not payments for current production. Sales of second hand goods, because the goods were counted in the year they were produced and counting them again would be duplication, although the commission earned by the dealer is counted as a current service. Purely financial transactions such as the purchase of shares or bonds, since no good or service is produced. The value of intermediate goods, because it is already contained in the value of the final good. And most non marketed output, including unpaid domestic work and subsistence production, because there is no price at which to value it.

7. "Per capita income is a good measure of the standard of living." Discuss. It is a useful first approximation and it is the figure used for international comparison, since it adjusts total income for the size of the population. But it is an average and says nothing about distribution, so it can rise while most households become poorer. It is measured in money and therefore ignores changes in the price level unless real figures are used, and it ignores differences in the cost of living between countries unless purchasing power parity is used. It also excludes non marketed production, unpaid work and leisure, and takes no account of the quality of the environment, of health or of education. Composite measures such as the human development index were designed to answer exactly these limitations.

1. Compensation of employees. Wages and salaries in cash and in kind, plus the employer's contribution to social security and pension.
2. Operating surplus. Rent and royalty from property, interest on capital lent, and profit. Profit itself divides into corporation tax, dividends and undistributed profits, and an answer that shows that split scores well.
3. Mixed income of the self employed. In India this matters more than anywhere, because a farmer, a shopkeeper or a rickshaw driver earns wages, rent, interest and profit at once and no separation is possible. The national accounts therefore have a separate category for it.

Adding these three gives net domestic product at factor cost. Add net factor income from abroad for national income.

What is excluded, and why.

• Transfer payments, such as pensions, scholarships and unemployment relief, because nothing was produced in return.
• Illegal incomes, because they cannot be recorded.
• Windfall gains such as a lottery prize, because no production accompanies them.
• Capital gains on the sale of an asset, because the asset was not produced this year.
• Corporate tax and personal income tax counted twice. These are parts of the incomes already counted, not additions to them.

Method three: expenditure

The rule. Sum all final expenditure on domestically produced goods and services.

The formula, which should be memorised:

GDP at market price = C + I + G + (X minus M)

• C, private final consumption expenditure: households and non profit institutions serving households.
• I, gross domestic capital formation: business investment in plant, machinery, buildings and the change in stocks, plus household investment in housing.
• G, government final consumption expenditure: what the State spends on goods and services for current use, valued at cost. Transfer payments are excluded.
• X minus M, net exports: exports minus imports. Imports are deducted because they were produced abroad and are already inside C, I and G.

Only final expenditure counts. Expenditure on intermediate goods is excluded, on the same reasoning as double counting in the production method.

The same economy measured three ways

The setting. An island economy for one year, in crore rupees. There are three producing units: a farm, a mill and a bakery, exactly as in the table above, with the numbers scaled up.

Production method. Farm value added 100, mill 60, bakery 100. Total value added 260.

Income method. The three units together paid wages of 150, rent of 30 and interest of 20, and their owners retained profit of 60. Total factor income 260.

Expenditure method. Households spent 240 on bread; the bakery added 20 to its stock of flour and equipment, which counts as investment. Total final expenditure 260.

Why the three agree. Because everything produced was either sold to a final buyer or added to stocks, and everything received for it was paid out to somebody as wages, rent, interest or profit. That is the circular flow. If in a real calculation the three differ, the difference is a measurement error and is recorded as errors and omissions, or discrepancies, in the published accounts, never suppressed.

Which method is used for which sector

No country uses one method for the whole economy, and knowing this is worth a paragraph.

• The production method is used where output is measurable in physical units: agriculture, mining, manufacturing, electricity.
• The income method is used where output cannot be measured directly but incomes can: public administration, defence, banking, education, health, professional services. The output of a government school is valued at what it cost to run.
• The expenditure method is used as a cross check on the whole, and it is the only one that gives the composition of demand, which is why the Economic Survey uses it to say how much of growth came from consumption, from investment and from net exports.

India's practice. The Ministry of Statistics and Programme Implementation, through the National Statistical Office, compiles the national accounts. Since the base year revision to 2011-12, the headline production side measure is gross value added at basic prices by industry of origin, and the headline demand side measure is GDP at market prices. Estimates are released as Advance, then Provisional, then First, Second and Third Revised, and the Statistical Appendix to the Economic Survey labels each. A figure quoted without its vintage is an unreliable figure.

The historical note an examiner sometimes wants. The first attempts to estimate India's national income were made by Dadabhai Naoroji in Poverty and Un-British Rule in India, whose estimate was part of his drain of wealth argument, and later by V. K. R. V. Rao. After independence the National Income Committee was appointed in 1949 under P. C. Mahalanobis, with D. R. Gadgil and V. K. R. V. Rao as members, and it produced the first official estimates. The Central Statistical Organisation, now part of the Ministry of Statistics and Programme Implementation, has done the work since 1954.

A worked example: what to include and what to leave out

Decide for each item whether it enters national income, and why. This is the commonest short question on the topic.

What beginners get wrong

"Add the sales of every firm." That is double counting. Add value added, or add final expenditure.

"National income is what the government collects." That is revenue, an entirely different quantity, and the subject of [The Sources of Public Revenue].

"The three methods sometimes give different answers, so one must be wrong." In principle they are identical. In practice the data come from different sources with different errors, and the published accounts carry a discrepancy line. That is honesty, not failure.

"Depreciation can be ignored." It is the difference between gross and net, and net is the figure that says what the economy actually has available.

Limits and criticism

It is only as good as the data. [The Difficulties of Measuring National Income in India] is the chapter on that.

Imputation is unavoidable and arguable. The imputed rent of owner occupied houses and the imputed value of a farmer's own produce are estimates, and different assumptions give different national incomes.

Revisions are large. An advance estimate can move by a percentage point when revised, which is why a growth rate should always be quoted with its vintage.

The base year matters. Changing the base year changes the level and sometimes the growth rate of the whole series, which is why the 2011-12 revision produced so much argument.

Quick revision

1. Three methods: production or value added, income, and expenditure. They measure the same circular flow at three points and must agree.
2. Production method: value of output minus intermediate consumption, summed over all units. The rule is avoid double counting.
3. Income method: compensation of employees plus operating surplus (rent, interest, profit) plus mixed income of the self employed, which matters most in India.
4. Expenditure method: GDP at market price = C + I + G + (X minus M). Only final expenditure; imports are deducted.
5. Excluded from all three: transfer payments, second hand sales, financial transactions, windfalls, illegal income, non marketed output.
6. In practice: production method for agriculture and industry, income method for services and government, expenditure method as a cross check and for the composition of demand.
7. India: compiled by MoSPI through the NSO, base year 2011-12, GVA at basic prices by industry of origin on the production side. Estimates run Advance, Provisional and Revised, and the vintage must be quoted.
8. History: Dadabhai Naoroji's estimate, then V. K. R. V. Rao, then the National Income Committee of 1949 under P. C. Mahalanobis, with the Central Statistical Organisation doing the work from 1954.

Test yourself

1. Describe the production method of measuring national income. The economy's producing units are classified into primary, secondary and tertiary sectors. For each unit the gross value of output is estimated as quantity multiplied by price, adjusted for the change in stocks, and the value of intermediate goods and services purchased is deducted to give gross value added at basic prices. Summing over all units and adding product taxes net of product subsidies gives GDP at market prices; deducting depreciation gives net domestic product, and adding net factor income from abroad gives national income. The essential precaution is to count only value added or only final goods, so as to avoid double counting.

2. What is double counting, and how is it avoided? Illustrate. Double counting is the error of including the value of the same output more than once by counting intermediate goods separately from the final good in which they are embodied. If a farmer sells wheat for 100, a miller sells flour for 160 and a baker sells bread for 260, adding all three gives 520 while the economy produced only 260. It is avoided either by counting only the final good, the bread at 260, or by counting the value added at each stage, which is 100 plus 60 plus 100 and comes to the same 260.

3. State the components of national income under the income method. Compensation of employees, comprising wages and salaries in cash and in kind and the employer's contribution to social security; operating surplus, comprising rent and royalty, interest and profit, with profit further divisible into corporation tax, dividends and undistributed profit; and mixed income of the self employed, which is important in India because farmers, shopkeepers and other own account workers earn wages, rent, interest and profit inseparably. Their sum is net domestic product at factor cost, to which net factor income from abroad is added to reach national income.

4. Give the expenditure method formula and explain each term. GDP at market price equals C plus I plus G plus exports minus imports. C is private final consumption expenditure by households and by non profit institutions serving them. I is gross domestic capital formation, that is investment in plant, machinery, buildings and housing together with the change in stocks. G is government final consumption expenditure on goods and services for current use, valued at cost, and it excludes transfer payments. Exports minus imports is net exports, imports being deducted because goods produced abroad are already included in C, I and G but were not produced domestically.

5. Why must the three methods give the same result? Because they measure the same circulation at three points. Whatever is produced is either sold or added to stocks, so the value of production equals the value of final expenditure. And the whole of the value produced accrues to somebody as wages, rent, interest, profit or mixed income, so the value of production also equals total factor income. In practice the three estimates are built from different data sources with different errors, so a residual difference appears and is published as errors and omissions rather than concealed.

6. Which method is used for which part of the Indian economy, and who compiles the accounts? The production method is used where physical output can be measured, in agriculture, forestry, fishing, mining, manufacturing and electricity. The income method is used where output cannot be measured directly, in public administration and defence, banking, education, health and professional services, whose output is valued largely at cost. The expenditure method serves as a cross check on the total and is the only one that shows the composition of demand. The accounts are compiled by the National Statistical Office in the Ministry of Statistics and Programme Implementation, with the base year 2011-12, and estimates are published as advance, provisional and revised.

7. Classify the following and give reasons: an old age pension, the imputed rent of an owner occupied house, the purchase of a government bond, and a farmer's own consumption of his grain. An old age pension is excluded, because it is a transfer payment made without any current production in return. The imputed rent of an owner occupied house is included, because the house yields a housing service which is consumed and which can be valued at the market rent of a comparable dwelling. The purchase of a government bond is excluded, because it is a financial transaction that transfers a claim rather than producing a good or service, although the interest later paid is treated separately. A farmer's own consumption of his grain is included by imputation, because it is production, it is measurable in physical units and it can be valued at market price.

The term to know is natural capital. MoSPI's own explanation attributes the term to the economist E. F. Schumacher and defines natural capital as the natural asset in its role of providing natural resource inputs and environmental services for economic production, covering both renewable and non renewable resources. Green accounting treats natural capital as an asset on the nation's balance sheet, so that using it up reduces wealth exactly as using up a machine does.

Where India stands, from the official record

The framework. The internationally agreed standard is the System of Environmental Economic Accounting (SEEA), adopted by the United Nations Statistical Commission, which sits alongside the System of National Accounts and uses the same concepts and classifications so that the two can be read together.

The Indian institutional history, from MoSPI's EnviStats FAQ 2025.

1. Many separate research studies had been done in India on forests, wetlands, coastal and marine systems and mangroves, but a full account could not be compiled from them, because the methods and definitions differed and the results could not be aggregated. That is worth stating in an answer, because it explains why a country with a great deal of environmental research had no environmental accounts.
2. To answer that, MoSPI constituted a high level Expert Group in 2011 under the chairmanship of Professor Sir Partha Dasgupta, Frank Ramsey Professor Emeritus of Economics at the University of Cambridge, with the mandate of developing a framework for green national accounts for India and a roadmap to implement it.
3. The Expert Group submitted its report, Green National Accounts in India: A Framework, in 2013, and recommended compiling the accounts of the SEEA Central Framework in a phased manner, beginning with asset accounts and supply and use tables.
4. Acting on that, the National Statistical Office began compiling environmental accounts in the SEEA framework in 2018 and has released them since, in the annual publication EnviStats India, whose Volume I is environment statistics and whose Volume II is the environment accounts.

What India therefore does and does not publish. India publishes environmental accounts: asset accounts for land, water, forests, minerals and energy, and ecosystem accounts covering extent, condition and services. It does not publish a single official headline number called Green GDP, and an answer that claims India reports one is wrong. The phased approach the Dasgupta Group recommended is deliberate: the asset accounts have to exist before any aggregate adjustment can be honest.

Why a single Green GDP figure is so hard to produce

This is the section that separates a good answer from a list, and every one of these is a real obstacle rather than an excuse.

1. Valuation. A forest's timber has a market price. Its role in holding soil, storing carbon, recharging groundwater and supporting species does not. Economists estimate such values by indirect methods, contingent valuation by asking people what they would pay, hedonic pricing by observing what buyers pay for cleaner locations, replacement cost by asking what an engineered substitute would cost, and each method gives a different number.

2. What counts as depletion. A renewable resource is depleted only if it is taken faster than it regenerates, so a sustainable yield figure must be agreed before anything can be deducted.

3. Data. Estimating the stock of groundwater under a district, or the condition of a wetland, requires physical measurement that most countries do not have at national scale.

4. Whose loss is it. A river polluted in one State harms people downstream in another. National accounting has no natural home for a cost that crosses a boundary.

5. Time. Carbon emitted this year damages a generation not yet born. Putting a present value on that requires a discount rate, and the choice of discount rate changes the answer by an order of magnitude. This was the central controversy in the economics of climate change and it is not settled.

6. It is politically inconvenient. A Green GDP figure will always be lower than the conventional one, and a growth rate calculated on it can be lower too. That is not a reason against publishing it, but it explains why adoption everywhere has been slow.

A worked example: two districts with the same GDP

The facts. Two districts each record gross value added of 1,000 crore rupees in a year.

District A earns it from mining. It extracted iron ore that took geological time to form, worth 300 crore on any reasonable valuation of the stock removed, and the run off from the workings has silted a river, costing 60 crore in lost irrigation and fisheries downstream.

District B earns it from software services and horticulture. It depleted no non renewable stock and its measured degradation is 10 crore.

Conventional accounting. Both districts contributed 1,000 crore. They are indistinguishable.

Green accounting.

• District A: 1,000 minus 300 minus 60 = 640 crore.
• District B: 1,000 minus 0 minus 10 = 990 crore.

What this shows, and it is the whole point of the concept. The conventional figure measures the flow and ignores the balance sheet. District A converted an asset into income and recorded the conversion as production. A student who can state that in one sentence has understood green accounting.

Where a lawyer meets it. Compensation for the acquisition of land under an environmental clearance, the assessment of damages for environmental harm, and the polluter pays principle all require exactly this kind of valuation, and the courts have had to do it without a settled method. Green accounting is the attempt to build that method at national scale.

The wider criticism of GDP, of which Green GDP is one answer

Green GDP is one of several corrections proposed to a measure everybody agrees is imperfect. An examiner who asks about the limitations of GDP as a measure of welfare wants this list.

GDP counts the wrong things. Rebuilding after a flood, treating illness caused by pollution and running prisons all add to GDP.

GDP misses the right things. Unpaid domestic and care work, overwhelmingly done by women, is a very large part of real production in India and appears nowhere. Leisure has no entry. Neither does the quality of what is produced.

GDP is silent on distribution. [Poverty and the Poverty Line] shows that a rising average is consistent with a growing number of poor people.

The alternatives proposed. The Human Development Index, published by the United Nations Development Programme from 1990 and built on the capability approach associated with Amartya Sen, combines income with life expectancy and education. The Genuine Progress Indicator and the older Measure of Economic Welfare of Nordhaus and Tobin adjust national income for leisure, pollution and unpaid work. Gross National Happiness, adopted by Bhutan, replaces the objective entirely.

The honest conclusion for an answer. None of the alternatives has displaced GDP, because GDP is comparable across countries and across time, is compiled to a common international standard, and is available quickly. The professional consensus is not to abandon it but to publish it alongside the accounts that show what it leaves out, which is precisely the programme the Dasgupta Group recommended and the National Statistical Office is executing.

What beginners get wrong

"Green GDP is GDP of the environmental sector." It is not a sector's output. It is total GDP with environmental deductions applied.

"India publishes Green GDP." India publishes environmental accounts under EnviStats India in the SEEA framework. It does not publish a single official Green GDP headline.

"Green GDP is always much smaller." How much smaller depends entirely on the valuation method, which is the difficulty rather than a detail.

"Deducting pollution damage is a new idea." The principle is the same one that already deducts depreciation of machinery to get from GDP to NDP. Green accounting extends an accepted rule; it does not invent one.

Quick revision

1. Green GDP = GDP minus depletion of natural resources minus the cost of environmental degradation, and sometimes minus defensive expenditure.
2. The logic: the accounts already deduct depreciation of produced capital, so consistency requires deducting the using up of natural capital.
3. Natural capital, a term MoSPI attributes to E. F. Schumacher, is the natural asset providing resource inputs and environmental services to production.
4. The framework is SEEA, the System of Environmental Economic Accounting, which sits alongside the System of National Accounts.
5. India's record: MoSPI constituted an Expert Group in 2011 under Professor Sir Partha Dasgupta; its report Green National Accounts in India: A Framework came in 2013 and recommended phased compilation under the SEEA Central Framework; the NSO has compiled environment accounts since 2018 and publishes them in EnviStats India.
6. India does not publish a single Green GDP figure, and saying it does is an error.
7. Six difficulties: valuation of non marketed services, defining depletion for renewables, physical data, harm that crosses boundaries, the discount rate for future damage, and political inconvenience.
8. Alternatives to GDP: Human Development Index (UNDP, from 1990), Genuine Progress Indicator, Measure of Economic Welfare, Gross National Happiness. None has displaced GDP; the working answer is to publish both.

Test yourself

1. Define Green GDP and explain the reasoning behind it. Green GDP is conventional gross domestic product adjusted by deducting the monetary value of the natural resources depleted during the year and the cost of the environmental degradation caused, so that output which was financed by running down natural capital is not treated as income. The reasoning is one of consistency: the accounts already deduct depreciation of produced capital such as machinery and buildings in moving from gross to net product, on the ground that what has been used up must be replaced before anything is available for consumption. Natural capital is used up in the same way, and the only reason it was ignored is that it was never bought and therefore never valued.

2. What are the two adjustments made in arriving at Green GDP? The first is depletion, the reduction during the year in the stock of natural resources used in production, such as minerals extracted, groundwater drawn beyond recharge, timber felled beyond regrowth and soil lost to erosion. The second is degradation, the cost of the deterioration in the quality of air, water, soil and ecosystems, including the value of ecosystem services lost. A third adjustment is sometimes made for defensive expenditure incurred only to prevent or repair environmental damage.

3. Trace India's institutional progress towards green national accounts. Numerous Indian studies on forests, wetlands and coastal and marine systems existed but could not be aggregated into an account, because their methods and definitions were not comparable. MoSPI therefore constituted a high level Expert Group in 2011 under Professor Sir Partha Dasgupta of the University of Cambridge to develop a framework for green national accounts and a roadmap for implementing it. The Group's report, Green National Accounts in India: A Framework, was submitted in 2013 and recommended compiling the accounts of the SEEA Central Framework in phases, beginning with asset accounts and supply and use tables. The National Statistical Office began compiling environmental accounts in the SEEA framework in 2018 and publishes them annually in EnviStats India.

4. Why is a single Green GDP figure difficult to compute? Because many of the services being valued have no market price, so that estimates depend on indirect techniques such as contingent valuation, hedonic pricing and replacement cost, each of which yields a different figure. Because depletion of a renewable resource can be defined only against an agreed sustainable yield. Because the physical data on stocks and conditions of resources are incomplete. Because damage often crosses State and national boundaries, so that the loss is not confined to the accounting unit. Because damage to future generations must be discounted to the present, and the choice of discount rate changes the answer greatly. And because the resulting figure is always lower than the conventional one, which makes its adoption politically uncomfortable.

5. Two districts each record output of 1,000 crore rupees. One is a mining district and one is a services district. How does green accounting distinguish them? Conventional accounting cannot distinguish them at all, because both recorded the same value added. Green accounting deducts, from the mining district, the value of the non renewable stock extracted, which was an asset converted into income rather than income earned, together with the cost of the degradation its workings caused downstream. The services district has little or nothing to deduct. The adjusted figures separate an economy that has grown by producing from one that has grown by consuming its own balance sheet, which is precisely what the conventional measure cannot show.

6. State four limitations of GDP as a measure of welfare and name two alternatives. GDP counts activity that repairs harm, such as the treatment of pollution related illness and reconstruction after a disaster, as though it were a gain. It omits unpaid domestic and care work, subsistence production and leisure. It is silent about distribution, so it can rise while poverty deepens. And it takes no account of the depletion of natural resources or of environmental damage, which is the gap Green GDP addresses. Among the alternatives are the Human Development Index published by the United Nations Development Programme since 1990, which combines income with life expectancy and education, and the Genuine Progress Indicator, which adjusts national income for pollution, unpaid work and other omissions. Neither has replaced GDP, and the practical answer has been to publish the environmental and social accounts alongside it.

5. Depreciation. The consumption of fixed capital is an estimate based on assumed lives for assets, not an observation. Different assumptions produce different net product.

6. The treatment of illegal and unrecorded activity. Income from smuggling, bribery and unaccounted trade is production in the economic sense and cannot be recorded.

7. Changes in quality and new goods. A given rupee buys a very different phone from the one it bought in 2011. The accounts treat both as one unit of the same thing, so real growth is understated where quality improves and overstated where it declines.

The practical difficulties, which are the India specific ones

1. Non monetised production. A large volume of output in rural India never passes through a market: grain kept for the family, fodder, firewood, milk consumed at home, houses built with family labour, services exchanged between neighbours. Only some of it is imputed. The rest is invisible.

2. The size of the unorganised sector. Most Indian workers are in enterprises that keep no formal accounts: small manufacturing units, retail traders, transport operators, construction workers, domestic workers, street vendors. Their contribution has to be estimated by taking a sample and blowing it up by an assumed number of units, and both the sample and the multiplier are uncertain.

3. Illiteracy and the absence of accounts. Even where an enterprise is willing to report, many small producers do not keep records that would answer the question. A farmer asked for the value of his output in a year is being asked something he has never computed.

4. Absence of occupational specialisation. A rural household commonly farms, keeps animals, drives a vehicle in the off season and runs a small shop. The income is one income and cannot be split between industries, which is why the accounts have a separate head for mixed income of the self employed rather than trying to divide it into wages, rent, interest and profit.

5. The statistical machinery, and the delay in it. Estimates rest on large surveys and censuses that are conducted at long intervals: the periodic labour force survey, the household consumption expenditure survey, the economic census, the agricultural census. Between two rounds the earlier structure has to be projected forward, and if the structure has changed the projection carries the error. India's last completed population census was in 2011, and every per capita figure since then has used a projected population.

6. Double counting in practice. Where the same output passes through several hands and each is surveyed separately, the risk is not theoretical.

7. Regional and seasonal variation. Prices for the same commodity differ across States and across the year, so a single valuation is an average that fits nowhere exactly.

8. Revision. The published figure is not one figure. It is a sequence: Advance Estimate, then Provisional, then First, Second and Third Revised Estimates, each based on more complete data. The Statistical Appendix to the Economic Survey labels the vintage of every figure, and a growth rate quoted without its vintage is not a reliable figure. A revision of half a percentage point is common.

9. Base year revision. The current series has base year 2011-12. Changing the base changes the level and sometimes the growth rate of the entire series, because it changes the weights of industries and the prices at which constant price output is valued.

A worked example: what one household hides from the accounts

The household. Ramesh and Sunita live in a village in Vidarbha with two children and Ramesh's mother.

What the accounts capture. Ramesh sells 18 quintals of cotton at the market, which is recorded as agricultural output. Sunita works 60 days under the rural employment guarantee scheme, and those wages are recorded.

What the accounts partly capture. They keep four quintals of jowar for the family. This is production for self consumption and the national accounts do impute it, but the imputation is based on an assumed retention rate for the district rather than on their actual decision.

What the accounts miss entirely.

• Sunita cooks, cleans, fetches water and cares for her mother in law for about seven hours a day. If a paid worker did the same work it would be counted in national income. Because she does it unpaid, it is not.
• Ramesh helps a neighbour build a cattle shed for four days and the neighbour helps him plough. No money changes hands and no output is recorded, though two sheds and two ploughed fields exist that did not before.
• The family collects firewood and fodder from common land.
• Ramesh drives a hired tempo for two months in the off season and is paid in cash without a record.

The size of the problem. Nobody can say precisely, which is itself the point. What can be said is the direction: India's measured national income is below its real production, that the gap is largest in exactly the households the accounts most need to describe, and that the gap has narrowed as the economy has monetised and as digital payments have brought small transactions into the record.

Where a law student meets it. Compensation and maintenance are frequently assessed on proved income, and a person whose real production is invisible to the accounts is usually also a person whose income is hard to prove in court. The measurement problem and the evidentiary problem have the same root.

What has improved

An answer that lists only difficulties is dated. Four genuine improvements should be named.

The base year revision to 2011-12 brought in enterprise level data from the corporate affairs database instead of relying on sample estimates for the corporate sector, and adopted gross value added at basic prices in line with the international standard.

Digital payments have made a large volume of small transactions recordable that previously were not.

The goods and services tax network produces a continuous record of business to business transactions, which improves the estimation of the unorganised sector where it is registered.

Administrative data from tax returns, provident fund accounts and company filings are increasingly used to supplement surveys.

None of these reaches the genuinely non monetised part of production, which remains the hard core of the problem.

What beginners get wrong

"The difficulties mean the figures are useless." They mean the figures are estimates with a margin of error and a stated vintage. That is true of every economic statistic in every country.

"Only poor countries have this problem." Every country imputes owner occupied rent and omits unpaid domestic work. The difference is one of degree, and the degree is large.

"A revision proves the earlier figure was dishonest." A revision is what happens when better data arrive, and a statistical system that never revised would be the suspicious one.

"Black money is simply added on." There is no way to add it on reliably. Estimates of the unaccounted economy vary so widely that quoting one as a fact is a mistake.

Quick revision

1. Conceptual difficulties: identifying final against intermediate goods; valuing government services, which are valued at cost; separating transfers from payments for production; the arbitrary line in imputation; estimating depreciation; illegal and unrecorded activity; and quality change and new goods.
2. Practical difficulties in India: non monetised production; the size of the unorganised sector; illiteracy and absence of accounts; absence of occupational specialisation, which forces the category mixed income of the self employed; inadequate and infrequent statistical machinery; practical double counting; regional and seasonal price variation; repeated revision; and base year change.
3. Unpaid domestic work is production and is not counted, so measured national income is below real production.
4. The last completed census is of 2011, so every per capita figure since is based on a projected population.
5. Estimates run Advance, Provisional and Revised. Always quote the vintage. The current base year is 2011-12.
6. Improvements: the 2011-12 base revision using corporate filings and GVA at basic prices, digital payments, the goods and services tax network, and greater use of administrative data.

Test yourself

1. Distinguish the conceptual from the practical difficulties in estimating national income. Conceptual difficulties concern what ought to be counted and how it should be valued: whether a good is final or intermediate, how to value government services that are not sold, which payments are transfers rather than payments for production, how far non marketed output should be imputed, how depreciation should be estimated, and how quality change should be handled. Practical or statistical difficulties concern the availability and reliability of data: non monetised production, the size of the unorganised sector, illiteracy and the absence of accounts, the absence of occupational specialisation, infrequent surveys, and the delays and revisions that follow.

2. Why does the absence of occupational specialisation create a difficulty, and how do the Indian accounts deal with it? Because a single rural household commonly farms, keeps livestock, runs a small trade and hires out labour or a vehicle, and receives one undivided income from all of it. The income method requires factor incomes to be classified as wages, rent, interest and profit, and no such division can be made where the same person supplies land, labour, capital and enterprise to the same activity. The Indian accounts therefore use a separate category, mixed income of the self employed, which records the combined return rather than attempting a split that the data cannot support.

3. How are government services valued in national income, and what problem does that create? They are valued at the cost of providing them, principally the salaries of the staff, because they are not sold and therefore have no market price. The problem is that cost is an input measure rather than an output measure, so a department that spends more without producing more is recorded as having produced more, and improvements in efficiency that reduce cost appear as a fall in output. No generally accepted alternative exists, which is why the convention has survived.

4. What is meant by non monetised production, and why does it matter in India? It is production that does not pass through a market and for which no money changes hands, such as grain retained for family consumption, fodder and firewood gathered, houses built with family labour, and services exchanged between neighbours. It matters in India because a considerable part of rural production takes this form and only some of it is imputed. The consequence is that measured national income understates real production, and the understatement is largest for the poorest households, which are precisely the ones policy most needs to measure.

5. Why is a national income figure always accompanied by its vintage? Because the same year's income is published several times as data become more complete: first as an advance estimate based on limited indicators, then as a provisional estimate, and then as first, second and third revised estimates. Revisions of half a percentage point in the growth rate are common. Quoting a figure without saying which estimate it is invites comparison between numbers built on different information, which is why the Statistical Appendix to the Economic Survey labels every entry.

6. State four ways in which the measurement of national income in India has improved. The base year revision to 2011-12 brought company level data from the corporate affairs database into the estimation of the corporate sector in place of sample based methods, and adopted gross value added at basic prices in line with international practice. The spread of digital payments has brought many small transactions into the record. The goods and services tax network provides a continuous record of business to business transactions, which improves estimation for the registered part of the unorganised sector. And administrative data from tax returns, provident fund accounts and company filings increasingly supplement periodic surveys. None of these reaches genuinely non monetised production, which remains the central difficulty.

Its features, listed for an answer. Rising national income; full or near full employment; rising prices and wages; high profits; heavy investment in plant and machinery; expansion of bank credit; rising share prices; a shortage of skilled labour and of some materials; and an increase in imports as domestic demand runs ahead of domestic supply.

Why it cannot last. Because the very conditions of a boom destroy it. Costs rise as materials and skilled labour become scarce. Interest rates rise. New capacity built during the boom comes into production and adds supply just as costs are highest. And somewhere the most optimistic investment turns out to be a mistake.

The upper turning point

The moment prosperity turns into recession. Some investment fails to earn what was expected; a lender contracts credit; confidence, which was self reinforcing on the way up, begins working the other way.

Phase two: recession

What it looks like. The turning point is now visible. Orders fall, unsold stocks rise, firms cut production and stop new investment. Employment falls. Prices and profits fall. Banks, seeing higher risk, restrict credit, which makes the contraction worse. Share prices fall. Failures begin among the weakest firms.

Its features. Falling output and employment; falling prices and profits; cancellation of investment plans; rising inventories, at first involuntarily and then deliberately run down; contraction of bank credit; falling share prices; and, crucially, a collapse of business confidence, which is the mechanism that turns a downturn into something worse.

Recession has a working definition used in reporting, though not a law of economics: two consecutive quarters of falling real gross domestic product.

Phase three: depression

What it looks like. The extreme of the downswing. Output and employment are at their lowest. Prices are at their lowest and may be falling still, which is deflation. Many firms have closed. Investment has stopped almost entirely, and there is heavy excess capacity, so a fall in the interest rate does little, because nobody wants to borrow to build what is already standing idle. Bank failures are possible.

Its features. Mass unemployment; general fall in prices, wages and incomes; heavy excess capacity; near zero investment; low interest rates that do not revive borrowing; contraction of world trade; and a deep pessimism that is itself part of the problem.

The historical reference every answer should have. The Great Depression that began in 1929 is the standard example, and it is the reason macroeconomics exists as a separate branch, as [Microeconomics and Macroeconomics] explains.

The lower turning point

The point at which the fall stops. Two things usually cause it. Plant and equipment wear out and eventually have to be replaced whether or not anybody feels optimistic, so replacement investment revives. And costs, wages, interest rates, material prices, have fallen far enough that an investment which was unprofitable at boom costs becomes profitable again.

Phase four: recovery or revival

What it looks like. Replacement orders reach the capital goods industries, which take on workers. Those workers spend, which raises demand for consumer goods. Firms find stocks running down, so they produce more. Employment, income, prices and profits all begin to rise. Credit expands. Confidence returns and the process becomes cumulative again, carrying the economy back into prosperity.

A caution to state. Recovery may be slow and false starts are common. That is why policy intervenes at this point rather than waiting.

The four phases compared

Other kinds of cycle, named

Economists distinguish cycles by length, and naming them is worth a line.

• Kitchin cycles, about three to five years, driven by inventory adjustment.
• Juglar cycles, about seven to eleven years, driven by investment in plant and equipment. This is the classic trade cycle and the one this chapter describes.
• Kuznets swings, about fifteen to twenty five years, associated with building and infrastructure.
• Kondratieff long waves, about fifty years, associated with major technological change.

A worked example: a cycle in one industry town

The town. A district whose economy rests on a cluster of auto component units supplying vehicle makers.

Prosperity. Vehicle sales are strong. The units run double shifts, hire 400 extra workers, and two proprietors order new presses on borrowed money. Shops in the town do well, land prices rise, and a new hospital and two schools open. Bank branches lend freely.

Upper turning point. Fuel prices rise sharply and interest rates on vehicle loans go up. Vehicle sales slow. The presses ordered eighteen months ago are delivered now, into a falling market.

Recession. Orders to the component units fall by a third. Overtime stops, then the second shift. The 400 extra workers go first. Unsold stock accumulates. The two proprietors cannot service their loans. Shops in the town see takings fall, and they in turn stop hiring.

Depression. Two of the seven units close. Half the town's workers are unemployed or on short time. Rents and land prices fall. The bank stops lending against local property. The new presses stand idle, so even at a lower interest rate nobody will buy machinery.

Lower turning point. After two years the surviving units' older machines fail and must be replaced. Wages and rents in the town are now much lower than in the neighbouring district, so a vehicle maker places a trial order there because it is cheap.

Recovery. The trial order becomes a standing one. A unit reopens under new ownership. Workers are recalled, the shops see takings rise, and the cumulative process begins again.

What the example teaches. Notice how the swing was violent in capital goods, the presses, and mild in the town's grocery trade; how confidence amplified both directions; and how the turning points came from replacement and from cost, not from anybody's decision to end the slump.

What beginners get wrong

"Trade cycles are regular, so the next slump can be dated." They are recurrent and not periodic. Nobody can date the next turning point, and an answer that implies otherwise is wrong.

"Recession and depression are the same." Recession is the downswing; depression is its extreme and prolonged form, with mass unemployment and falling prices. Every depression begins as a recession; most recessions do not become depressions.

"A cycle is the same as inflation." Inflation is a rise in the general price level. It typically accompanies a boom, but an economy can have inflation with stagnant output, which was called stagflation when it occurred in the 1970s and which the simple cycle does not describe.

"A falling growth rate is a recession." Growth falling from eight per cent to six is a slowdown. A recession requires output to fall, not merely to grow more slowly. The distinction matters in India, where the economy has continued to grow through periods described in the newspapers as slumps.

Limits of the analysis

The four phase description is a stylisation. Real cycles are irregular in length and depth, and some have no clear depression at all.

It does not explain what causes the cycle. That is the subject of the next chapter, and the four phase description is compatible with several competing explanations.

Modern policy has changed the shape. Deposit insurance, automatic stabilisers such as unemployment benefit and progressive taxation, active monetary policy and coordinated fiscal action have made deep depressions rarer than they were before 1945, though not impossible.

A developing economy's fluctuations have different causes. In India, the monsoon, world commodity prices and capital flows have historically mattered more than the classic investment cycle.

Quick revision

1. Trade cycle: recurrent but not periodic fluctuation in aggregate economic activity, general across sectors, cumulative and wave like, felt most in capital and durable goods, and international in transmission.
2. Four phases: prosperity, recession, depression, recovery, joined by an upper turning point and a lower turning point.
3. Prosperity: rising output, employment, prices, profits, investment and credit; optimism; ends because costs and interest rates rise and new capacity arrives.
4. Recession: falling orders, rising unsold stock, cancelled investment, contracting credit, collapsing confidence. Working definition: two consecutive quarters of falling real GDP.
5. Depression: mass unemployment, lowest prices, heavy excess capacity, investment near zero, low interest rates ineffective. The Great Depression from 1929 is the standard example.
6. Recovery: driven by replacement investment and by costs having fallen far enough, then cumulative.
7. By length: Kitchin three to five years, Juglar seven to eleven, Kuznets fifteen to twenty five, Kondratieff about fifty.
8. Recession is not depression, and a fall in the growth rate is not a recession.

Test yourself

1. Define a trade cycle and state its characteristics. A trade cycle is the recurrent fluctuation in the level of aggregate economic activity of a country, in which periods of expansion in output, income, employment, prices and profits alternate with periods of contraction. Its characteristics are that it is recurrent but not periodic, so no fixed interval can be stated; that it is general and synchronised across sectors rather than confined to one industry; that it is cumulative and self reinforcing in both directions; that it strikes capital goods and durable consumer goods industries far harder than the industries producing necessities; and that it is transmitted internationally through trade and capital flows.

2. Describe the four phases of a trade cycle. In prosperity, output, employment, income, prices and profits are high and rising, investment is heavy, bank credit expands and optimism is general. At the upper turning point some investment disappoints and confidence begins to fall. In recession, orders decline, unsold stocks accumulate, investment plans are cancelled, employment and prices fall, credit contracts and confidence collapses. In depression, output and employment are at their lowest, prices may still be falling, excess capacity is heavy and investment nearly ceases, so that even low interest rates fail to revive borrowing. At the lower turning point worn out equipment must be replaced and costs have fallen far enough to make investment profitable again, and in recovery replacement orders reach the capital goods industries, employment and incomes rise, stocks run down and the cumulative process carries the economy back to prosperity.

3. Distinguish recession from depression. Recession is the downward phase of the cycle, in which output, employment, prices and profits are falling from the peak; it is often identified in practice by two consecutive quarters of falling real gross domestic product. Depression is the extreme and prolonged form of that downswing, marked by mass unemployment, a general fall in prices and wages, heavy excess capacity, near cessation of investment and widespread business failure. Every depression begins as a recession, but most recessions do not deepen into a depression.

4. Why do capital goods industries suffer more in a trade cycle than consumer goods industries? Because the purchase of a capital good or a consumer durable can be postponed, while the purchase of food, fuel and other necessities cannot. When incomes fall or the future looks uncertain, households defer a car or a house and firms defer new machinery altogether, so demand for those goods falls sharply. Demand for necessities is inelastic and changes little. The result is that fluctuations in aggregate activity are magnified in the industries producing machinery, construction materials and durables, and muted in those producing everyday consumption goods.

5. What brings a depression to an end? Two forces, neither of which depends on a return of confidence. First, plant, machinery and equipment continue to wear out during the depression and must eventually be replaced if production is to continue at all, so replacement investment revives and orders reach the capital goods industries. Second, costs fall during the downswing: wages, rents, material prices and interest rates are all far lower than at the peak, so an investment that was unprofitable at boom costs becomes profitable again. Once the first orders are placed, employment and incomes rise and the process becomes cumulative.

6. Name the four types of cycle distinguished by length. Kitchin cycles of roughly three to five years, associated with the adjustment of inventories; Juglar cycles of roughly seven to eleven years, associated with investment in plant and equipment, which is the classic trade cycle; Kuznets swings of roughly fifteen to twenty five years, associated with building and infrastructure; and Kondratieff long waves of about fifty years, associated with major clusters of technological change.

7. "India's growth rate fell from 8 per cent to 6 per cent, so India was in recession." Comment. The statement is wrong. A recession requires the level of output to fall, not merely to grow more slowly. A decline in the growth rate from eight to six per cent is a slowdown in which the economy is still expanding, and both output and employment are higher at the end of the year than at the beginning. The practical test used in reporting is two consecutive quarters of falling real gross domestic product, which is a fall in the level. The distinction matters particularly in India, where periods described in public discussion as slumps have generally been periods of slower positive growth.

3. The under consumption theory: Malthus, Sismondi, Hobson

The claim. The cycle arises because consumption does not keep pace with production. Incomes are distributed unequally; the rich save a large part of theirs; so the goods produced cannot all be sold.

The remedy implied is redistribution towards those who spend a larger share of income, which is why the theory has always been associated with arguments for higher wages and for social spending.

The criticism. It explains a tendency to depression better than it explains a recurring cycle.

4. The psychological theory: A. C. Pigou

The claim. The cycle is driven by waves of optimism and pessimism among businessmen, which spread by imitation and overshoot in both directions.

The mechanism. Optimism causes over investment; when results disappoint, the error is discovered by many people at once and optimism turns into pessimism, which causes investment to fall further than the facts warrant.

The criticism. Psychology magnifies a cycle rather than starting it. But no explanation that leaves out expectations can account for the speed of a turning point, and Keynes's phrase about the animal spirits of entrepreneurs makes the same point from within a different theory.

5. The innovation theory: Joseph Schumpeter

The claim. The cycle is the way a capitalist economy absorbs innovation.

The mechanism. An entrepreneur introduces an innovation, a new product, a new process, a new market, a new source of supply, or a new form of organisation, financed by bank credit. The innovation earns high profits. Imitators rush in, borrowing to copy it, and the resulting investment produces the boom. When the innovation is fully diffused, the extra profit disappears, credit is repaid, and the contraction follows. The old firms that cannot adapt are destroyed, which Schumpeter called creative destruction.

Why it matters for this course. It is the strongest argument against treating all monopoly profit as waste, which is the point made in [Monopoly]: the temporary profit from being first is what pays for innovation.

6. The Keynesian explanation

The claim. Fluctuations arise from changes in aggregate demand, and above all in the volatile component of it, investment.

The mechanism, in three parts.

• The marginal efficiency of capital, meaning the expected return on new investment, depends on expectations about a future nobody knows, so it is inherently unstable.
• The multiplier. An increase in investment raises income by more than itself, because the wages paid become somebody's spending, which becomes somebody else's income, and so on. The size of the multiplier depends on the proportion of extra income that is spent, and a leakage into saving, taxes or imports reduces it. This is the circular flow of [The Circular Flow of Income] measured.
• The multiplier and the accelerator together produce a self sustaining cycle: investment raises income through the multiplier, rising income raises investment through the accelerator, until capacity or credit limits it, and then the same interaction runs in reverse.

The policy conclusion, which is the reason the theory changed the world: an economy can settle at an equilibrium with heavy unemployment and stay there, so the State must act on demand rather than wait.

What actually causes fluctuations in India

An answer written only from the classical theories misses the Indian case, and MU's own emphasis on the Indian economy in Module II makes this worth a paragraph.

The monsoon. For most of India's post independence history, the single largest source of year to year fluctuation was rainfall, working through agricultural output, rural incomes and food prices. Irrigation, buffer stocks and the falling share of agriculture in output have reduced this but not removed it.

World commodity prices, particularly crude oil. India imports a large share of the crude it uses, so a rise in the world price raises costs across the economy, worsens the trade balance and squeezes the government's finances at once.

Capital flows. Since liberalisation, portfolio flows respond to interest rates and risk appetite abroad, and a sudden reversal tightens domestic financial conditions independently of anything happening in India.

The global cycle. The financial crisis of 2008 and the pandemic of 2020 both transmitted to India through trade, capital flows and confidence.

A caution to state honestly. India has not experienced a classical depression since independence, and its cycle is mostly a cycle in the growth rate rather than in the level of output, except in the year of the pandemic. An answer that describes Indian fluctuations in the language of the Great Depression is describing the wrong economy.

The control measures

The examiner asks for these under "measures to control trade cycles", and they divide into three.

Monetary measures, operated by the Reserve Bank

In a boom, restrain credit and demand; in a depression, expand it.

• The policy repo rate. Raising it makes borrowing dearer and cools demand; lowering it does the reverse. Under section 45ZB of the RBI Act 1934 the rate is set by a six member Monetary Policy Committee constituted by the Central Government, which determines the policy rate required to achieve the inflation target.
• The inflation target itself. Under section 45ZA the Central Government, in consultation with the Bank, determines the inflation target in terms of the consumer price index once every five years and notifies it in the Official Gazette. On its second review, on 25 March 2026, the Central Government retained the target for the five years from 1 April 2026 to 31 March 2031 at 4 per cent, with an upper tolerance of 6 per cent and a lower tolerance of 2 per cent.
• Cash reserve ratio and statutory liquidity ratio, open market operations, and the standing facilities. These are set out fully in [What Determines the Money Supply, and How the RBI Controls It].
• Selective or qualitative controls, such as margin requirements on loans against particular commodities or securities, which aim at one sector rather than the whole economy.

The limitation to state. Monetary policy is more reliable against a boom than against a depression. Rates can always be raised; they cannot usefully be cut below a floor, and in a depression with heavy excess capacity cheap money finds no borrower. That asymmetry is the standard criticism.

Fiscal measures, operated by the government

In a depression, spend more and tax less; in a boom, the reverse.

• Public works and capital expenditure. Roads, railways, housing and irrigation put income directly into households and, through the multiplier, into the rest of the economy.
• Taxation. Cutting taxes in a downswing leaves more in households' hands; raising them in a boom withdraws demand.
• Transfer payments and employment guarantees. These reach the households most likely to spend and are quick to operate.
• Automatic stabilisers. Progressive income tax and unemployment or employment guarantee spending move in the stabilising direction without anybody deciding anything: tax collections fall automatically when incomes fall, and guarantee scheme spending rises automatically when private work is scarce.
• The statutory frame. The FRBM Act 2003 sets fiscal targets, and section 4 requires the Central Government to limit the fiscal deficit and to endeavour to reduce debt in accordance with prescribed levels. The proviso to section 4(2) is the escape clause: the annual fiscal deficit target may be exceeded on the ground of national security, act of war, national calamity, collapse of agriculture severely affecting farm output and incomes, structural reforms in the economy with unanticipated fiscal implications, or a decline in real output growth of a quarter by at least three percentage points below its average of the previous four quarters. Section 4(3) caps any such deviation at one half of one per cent of gross domestic product in a year, and section 4(5) requires a statement explaining the reasons and the path of return to be laid before both Houses of Parliament. The Act is symmetrical: section 4(4) requires the deficit to be cut by at least a quarter of a per cent of gross domestic product where a quarter's real growth runs three percentage points above its four quarter average. Section 7 adds the machinery of compliance, a half yearly review placed before both Houses and, by section 7(3)(a), a bar on any other deviation without the approval of Parliament. That structure is exactly designed for the problem in this chapter: a rule for ordinary years and a lawful, capped and accountable exception for a slump.

Direct and structural measures

• Price and distribution controls in a period of shortage, with the limits described in [How Demand and Supply Together Set a Price].
• Buffer stocks and procurement, which stabilise farm incomes and food prices, treated in [Food Security: What It Means and How India Provides It].
• Regulation of the financial system, because financial failure is the mechanism that turns a recession into a depression. Deposit insurance, capital requirements for banks and supervision are as much anti cyclical measures as any interest rate.
• International coordination, because a cycle transmitted through trade cannot be answered by one country alone.

A worked example: the same slump answered three ways

The situation. A sharp fall in world demand cuts India's exports. Order books in textiles and engineering fall by a quarter. Factories cut shifts.

A monetary answer. The Monetary Policy Committee, seeing inflation below the target set under section 45ZA, cuts the policy repo rate and injects liquidity. Borrowing becomes cheaper, and firms that were going to postpone a purchase of machinery bring it forward. The limit: a firm with a quarter of its capacity idle does not buy a machine because money is cheap. Monetary policy helps and does not by itself fill the gap.

A fiscal answer. The government brings forward capital expenditure on roads and housing and expands employment guarantee spending. Contractors hire, wages are paid, and the multiplier carries the spending into shops and services. The limit: the fiscal deficit widens beyond the FRBM path, which is why the Act contains an escape clause in the proviso to section 4(2), a cap of half a per cent of gross domestic product on the deviation in section 4(3), and a duty under section 4(5) to lay a statement before both Houses, rather than an absolute prohibition.

A structural answer. Nothing in either of the above changes the fact that the exports were lost. Diversifying markets, improving competitiveness and supporting the affected industries to move up the value chain are slower and are the only permanent answer. This is where Module IV, and in particular [Commercial Trade Policy], joins Module I.

What a good answer says at the end. The three are complements, not alternatives. Monetary policy is fast and blunt; fiscal policy is powerful and slow to reverse; structural policy is slow and permanent.

What beginners get wrong

"There is one accepted theory of the trade cycle." There is not, and saying so is the mark of a good answer rather than a weak one. Each theory identifies a real mechanism, and the mechanisms operate together.

"Cheap money always ends a depression." In a depression with heavy excess capacity it may not, and that asymmetry is why fiscal policy came to be relied on after 1936.

"The accelerator says investment rises when consumption rises." It says investment responds to the change in consumption, which is why investment can fall in absolute terms while consumption is still rising, merely more slowly. That distinction is what makes the idea worth knowing.

"Automatic stabilisers are a policy decision each year." They work without a decision, which is exactly their advantage.

Quick revision

1. Six theories: monetary (Hawtrey, bank credit); over investment (Hayek, and the acceleration principle); under consumption (Malthus, Sismondi, Hobson); psychological (Pigou, waves of optimism and pessimism); innovation (Schumpeter, creative destruction); and Keynesian (unstable marginal efficiency of capital, the multiplier, and multiplier plus accelerator).
2. The acceleration principle: investment depends on the change in consumption demand, so a small change in consumption produces a magnified change in investment. It explains why capital goods swing hardest.
3. Indian fluctuations come mainly from the monsoon, world crude prices, capital flows and the global cycle, and are mostly cycles in the growth rate rather than in the level of output.
4. Monetary measures: the policy repo rate set by the Monetary Policy Committee under section 45ZB of the RBI Act 1934; the inflation target under section 45ZA, retained on 25 March 2026 at 4 per cent with a 6 and 2 per cent band for 1 April 2026 to 31 March 2031; cash reserve ratio, statutory liquidity ratio, open market operations and selective controls.
5. Monetary policy is asymmetric: more reliable against a boom than a depression.
6. Fiscal measures: public works and capital expenditure, tax changes, transfers and employment guarantees, and automatic stabilisers that act without a decision. The FRBM Act 2003 sets the targets in section 4; the proviso to section 4(2) is the escape clause (national security, act of war, national calamity, collapse of agriculture, structural reform with unanticipated fiscal implications, or a quarter's real growth three points below its four quarter average); section 4(3) caps the deviation at half a per cent of GDP; section 4(5) requires a statement of reasons and of the path back before both Houses; and section 4(4) requires the deficit to be cut when growth runs three points above trend.
7. Structural measures: buffer stocks and procurement, financial regulation, and diversification of markets.
8. The three kinds of measure are complements, differing in speed, power and permanence.

Test yourself

1. Explain the acceleration principle and why it matters. The acceleration principle states that the demand for capital goods depends not on the level of consumption demand but on the rate of change of it. A firm holding ten machines each lasting ten years replaces one a year; if demand for its product rises by a fifth it must hold twelve machines, so it orders three in that year, tripling its purchases of machinery in response to a twenty per cent rise in consumption. If consumption then merely stops growing, the two extra orders disappear and machinery orders fall by two thirds. It matters because it explains, without invoking psychology, why capital goods industries fluctuate far more violently than consumer goods industries, and why investment can fall absolutely while consumption is still rising more slowly than before.

2. State Schumpeter's innovation theory of the trade cycle. Schumpeter held that the cycle is the way a capitalist economy absorbs innovation. An entrepreneur introduces an innovation, whether a new good, a new method of production, a new market, a new source of supply or a new form of organisation, financed by bank credit, and earns high profits. Imitators borrow to copy it, and the resulting cluster of investment produces the boom. Once the innovation has been fully diffused the extra profit disappears, credit contracts and the downswing follows, destroying the firms that could not adapt, a process he called creative destruction. The theory implies that the cycle is the price of technological progress rather than a defect to be abolished.

3. What is the multiplier, and what determines its size? The multiplier is the ratio by which a change in autonomous expenditure, typically investment, changes national income, and it is greater than one because the income paid out in the first round is partly spent, becoming income in the second round, and so on. Its size depends on the proportion of each additional rupee of income that is spent on domestically produced goods, so it is reduced by every leakage from the circular flow: saving, taxation and imports. A high propensity to save or a high import content therefore weakens the effect of a given stimulus.

4. Describe the monetary measures used to control a trade cycle, and state their limitation. In a boom the central bank restrains credit by raising the policy repo rate, raising the cash reserve ratio and selling securities in open market operations, and it may impose selective controls such as higher margin requirements on loans against particular commodities. In a depression it does the reverse. In India the policy rate is determined by a six member Monetary Policy Committee constituted under section 45ZB of the Reserve Bank of India Act 1934, to achieve the inflation target notified by the Central Government under section 45ZA, which on the review of 25 March 2026 was retained at four per cent with an upper tolerance of six and a lower of two for the period from 1 April 2026 to 31 March 2031. The limitation is asymmetry: rates can always be raised to restrain a boom, but in a depression with heavy excess capacity cheap credit finds no borrower, so monetary policy is a weaker instrument on the downswing.

5. What are automatic stabilisers, and why are they valuable? They are features of the fiscal system that move counter cyclically without any fresh decision being taken. A progressive income tax collects proportionately less when incomes fall and more when they rise, so it cushions the fall in disposable income and restrains a boom. Spending that expands when private work is scarce, such as an employment guarantee scheme or unemployment relief, does the same from the expenditure side. They are valuable because they act immediately, without the delays of legislation and administration that afflict discretionary measures, and because they reverse themselves automatically when conditions improve.

6. How does the FRBM Act 2003 accommodate the need for fiscal action in a slump? The Act sets fiscal responsibility targets, requiring the Central Government under section 4 to limit the fiscal deficit and to work towards prescribed levels of debt. It does not, however, make those targets absolute. The proviso to section 4(2) allows the annual fiscal deficit target to be exceeded on specified grounds: national security, act of war, national calamity, collapse of agriculture severely affecting farm output and incomes, structural reforms in the economy with unanticipated fiscal implications, and a decline in real output growth of a quarter by at least three percentage points below its average of the previous four quarters. Section 4(3) limits any such deviation to one half of one per cent of gross domestic product in a year, and section 4(5) requires a statement explaining the reasons and the path of return to the prescribed targets to be laid before both Houses of Parliament. Section 4(4) works the other way, requiring the deficit to be reduced by at least a quarter of a per cent of gross domestic product when a quarter's real growth runs three points above its four quarter average, and section 7 requires a half yearly review of receipts and expenditure to be placed before both Houses. The design is a rule for ordinary years with a lawful, capped and accountable exception for extraordinary ones, which is precisely what counter cyclical fiscal policy requires.

7. Do the classical theories of the trade cycle describe Indian fluctuations well? Only partly. The mechanisms they identify, unstable investment, the acceleration of capital goods demand, the amplification of movements by credit and by expectations, all operate in India. But the dominant sources of year to year fluctuation in India have historically been the monsoon working through agriculture and food prices, the world price of crude oil working through costs and the external accounts, portfolio capital flows responding to conditions abroad, and the transmission of global cycles through trade. India has also not experienced a classical depression since independence, and its cycle has generally been a cycle in the rate of growth rather than in the level of output, the pandemic year being the exception. An answer should therefore state the theories and then say which mechanisms actually dominate in the Indian case.