What Quality Means
Chapter Twenty-Two
Syllabus topic Module 1, "Definition of Quality and Quality Assurance: Understanding quality"
Pages 116 to 119 of 622
In one line
Quality is how well something does what it is meant to do for the people who depend on it; the standards make that precise as the degree to which a product's characteristics fulfil its requirements.
In the wording a student can write in an examination: ISO 9000 defines quality as the "degree to which a set of inherent characteristics ... of an object ... fulfils requirements", where a requirement is a "need or expectation that is stated, generally implied, or obligatory". Two classic short definitions sit behind it: Joseph Juran's fitness for use and Philip Crosby's conformance to requirements. David Garvin (1984) showed that people mean five different things by quality: transcendent, product-based, user-based, manufacturing-based and value-based.
Why "quality" needs defining at all
Everybody uses the word and almost nobody means the same thing by it. A student says ExamReg is good quality because it looks modern; the exam cell says so because it charges the right fees; the IT cell because it never crashes; the principal because it cost less than expected. All four are talking about quality, and they could each be satisfied while the others are not.
David Garvin, writing in MIT Sloan Management Review in the autumn of 1984, found the same confusion in the research literature: scholars in philosophy, economics, marketing and operations management had studied quality, "but each group has viewed it from a different vantage point", producing "a host of competing perspectives". A testing and quality course cannot proceed on a word with four meanings. It needs one definition to measure against, and an understanding of the others so that no stakeholder's meaning is forgotten.
ISO's definition
The international quality management standard's vocabulary, ISO 9000, now in its 2026 edition, defines quality in one sentence. ISO's own summary on its website gives it: quality is the "degree to which a set of inherent characteristics [or distinguishing features] of an object", where an object is "anything perceivable or conceivable, such as a product, service, process, person, organization, system or resource", "fulfils requirements."
Take the definition apart; every word is doing work.
- Degree. Quality is a scale, not a yes or no. A product has more or less of it.
- Inherent characteristics. Characteristics the object has in itself, such as correctness, speed or security, not ones assigned to it from outside, such as its price or its owner.
- Of an object. Anything: a program, a service, a process, even an organisation. The definition applies to the testing process as much as to the software.
- Fulfils requirements. Quality is measured against requirements, and the standards define a requirement broadly: a "need or expectation that is stated, generally implied, or obligatory" (SEVOCAB, from ISO/IEC 19770-1:2017).
What Quality Means
The word "implied" in the last line matters as much as any. A student never writes down the portal must not show my marks to someone else, but it is an expectation that is generally implied, and a portal that breaks it has poor quality however well it meets its written specification. The standards' word for fulfilling a requirement is conformity, and its opposite, a nonconformity, is the "non-fulfillment of a requirement".
Fitness for use, and conformance to requirements
ASQ, the American Society for Quality, records in its glossary that quality is "A subjective term for which each person or sector has its own definition", and gives two technical meanings: "the characteristics of a product or service that bear on its ability to satisfy stated or implied needs" and "a product or service free of deficiencies". It then names the two classic short definitions: "According to Joseph Juran, quality means 'fitness for use'; according to Philip Crosby, it means 'conformance to requirements.'"
| Fitness for use (Juran) | Conformance to requirements (Crosby) | |
|---|---|---|
| Asks | Does it serve the user's actual purpose? | Does it meet what was specified? |
| Judged by | The user, in use | Measurement against the specification |
| Strength | Keeps the user's real need in view | Objective, measurable, testable |
| Weakness | Hard to measure; users differ | A product can conform to a wrong specification |
| In testing terms | Validation | Verification |
The last row connects this chapter to the rest of the syllabus. Checking conformance to requirements is verification; checking fitness for use is validation. Chapter Four's seventh principle, the absence-of-defects fallacy, is exactly the gap between the two: software can conform perfectly and still not be fit for use. Verification and validation have their own chapter (Chapter Twenty-Six).
Garvin's five approaches to quality
Garvin's article identifies "five major approaches to the definition of quality": "(1) the transcendent approach of philosophy; (2) the product-based approach of economics; (3) the user-based approach of economics, marketing, and operations management; and (4) the manufacturing-based and (5) value-based approaches of operations management." Each is a way a real person judges software.
| Approach | Quality is ... | How a person using it judges ExamReg |
|---|---|---|
| Transcendent | Something recognised on sight but hard to define | It just feels solid and well made |
| Product-based | A measurable amount of desirable attributes the product has | Counts the features: backlog papers, concessions, online payment, hall ticket download |
| User-based | Whatever satisfies the particular user | A first-year student: I filled it in five minutes without help |
| Manufacturing-based | Conformance to the specification: getting it right the first time | The test lead: every requirement verified, no open defect |
| Value-based | Performance at an acceptable price | The principal: it does what the paper form did, faster, for the budget |
What Quality Means
The practical lesson is that a quality plan has to satisfy several approaches at once, because a project has stakeholders who use each of them. ExamReg's tests serve the manufacturing-based view; its usability sessions serve the user-based view; its budget serves the value-based view. A project that pleases only one of its judges has not delivered quality in the eyes of the others.
Quality is not grade
One distinction clears up a common confusion. SEVOCAB defines grade as a "scalar, qualitative measure or ranking to distinguish the relative fitness for use of similar items". A budget smartphone and a premium one are different grades; either can be of high or low quality. A low-grade product is not a failure; a low-quality product is.
For software, grade is the set of features and capabilities chosen (a basic ExamReg without online payment is a lower grade than one with it); quality is how well whichever grade was chosen fulfils its requirements. A basic ExamReg that charges every fee correctly and never crashes has higher quality than a feature-rich one that overcharges students.
Satisfaction: quality as the customer experiences it
The standards also name the outcome that quality is for. Customer satisfaction is the "state of fulfillment in which the needs of a customer are met or exceeded for the customer's expected experiences as assessed by the customer at the moment of evaluation" (SEVOCAB, from ISO/IEC/IEEE 24765). Three phrases in it are worth an examiner's attention: the needs are met or exceeded; it is assessed by the customer, not by the supplier; and it is judged at the moment of evaluation, so it can change. A portal that satisfied students in May can disappoint them in November, when their expectations have risen or a competitor has shown them something better.
Worked example: is ExamReg release 2.0 of good quality?
| Question | Evidence | Judgement |
|---|---|---|
| Does it conform to its stated requirements? | 412 test cases passed; one defect open, of minor severity | High conformance (manufacturing-based view) |
| Does it meet implied needs? | Security testing found no way to see another student's data; no requirement had said so explicitly | Implied need met |
| Is it fit for use by first-year students? | Nine of ten completed the form unaided in usability sessions | Fit for use, with one improvement to make (user-based view) |
| What grade is it? | Online payment, backlog papers, hall ticket download; no mobile app | A middle grade, chosen deliberately |
| Is it good value? | Delivered within budget; replaced three weeks of manual form checking | Good value (value-based view) |
A single-word answer, yes, would hide everything useful in the table. The honest answer is that release 2.0 has high conformance, meets the implied needs that were checked, is fit for use with one improvement, and is good value at its grade.
What Quality Means
What it does not mean
Quality does not mean luxury or expense. It is the degree to which requirements are fulfilled; a simple, cheap product can have excellent quality.
Quality is not only conformance to the written specification. Implied needs count, and a product can conform to a wrong specification.
Quality is not only the user's opinion either. Satisfaction is assessed by the customer, but conformance is measured objectively; both matter.
Quality is not a yes or no. ISO's definition begins with "degree".
Quick revision
- Quality (ISO 9000:2026, via ISO): "degree to which a set of inherent characteristics ... of an object ... fulfils requirements".
- Requirement: a need or expectation that is stated, generally implied, or obligatory. Conformity: fulfilment of a requirement; nonconformity: non-fulfilment.
- Juran: fitness for use (validation). Crosby: conformance to requirements (verification).
- Garvin (MIT Sloan Management Review, Fall 1984): five approaches: transcendent, product-based, user-based, manufacturing-based, value-based.
- Grade ranks similar items by capability; it is not quality.
- Customer satisfaction: needs met or exceeded, as assessed by the customer at the moment of evaluation.
Test yourself
1. Define quality as ISO 9000 does, and explain its key terms. Quality is the degree to which a set of inherent characteristics of an object fulfils requirements. Degree makes it a scale; inherent characteristics belong to the object itself, not assigned ones like price; an object can be a product, service, process or organisation; and requirements are needs or expectations that are stated, generally implied or obligatory.
2. Distinguish Juran's and Crosby's definitions of quality. Juran defined quality as fitness for use: whether the product serves the user's actual purpose. Crosby defined it as conformance to requirements: whether the product meets what was specified. The first corresponds to validation, the second to verification.
3. List Garvin's five approaches to quality with an example of each. Transcendent (recognised on sight), product-based (the amount of desirable attributes, such as features), user-based (whatever satisfies the user), manufacturing-based (conformance to specification) and value-based (performance at an acceptable price).
4. Distinguish quality from grade. Grade ranks similar items by their capabilities or features; quality is how well an item of any grade fulfils its requirements. A low-grade product can have high quality, and a high-grade one low quality.
5. Why does the word "implied" in the definition of requirement matter to a tester? Because users expect things they never write down, such as privacy of their data, and a product that breaks an implied need has poor quality even if it meets its written specification; testers must therefore test implied needs too.
The rest of this subject
These notes are cut from the University's printed syllabus. Open the syllabus itself, or the past papers, for the same subject.