The Deterrent and Preventive Approaches

In one line

The deterrent approach punishes in order to frighten people out of offending; the preventive approach punishes in order to take away the offender's ability to offend, and the two are constantly confused because a prison sentence does both.

In the wording a student can write in an exam: the deterrent approach justifies punishment by its effect on the will, holding that the prospect of the penalty will dissuade the offender and others from committing the offence, and it is divided into general deterrence, aimed at the public, and special or particular deterrence, aimed at the offender; the preventive or incapacitative approach justifies punishment by its effect on the capacity to offend, holding that a person imprisoned, disqualified or executed is thereby prevented from committing further offences against the public.

Deterrence

The two kinds

General deterrence operates on everybody except the offender. The sentence is a public message: this is what happens. Bentham regarded this as the principal end of punishment, because it operates on the whole population rather than on one person.

Special or particular deterrence operates on the offender, who is expected to weigh the experience and decline to repeat it.

What deterrence assumes

The assumptions are what an examiner is testing, because each one can fail.

A rational calculator. The person weighs the expected gain against the expected cost before acting.

Knowledge of the penalty. They must know roughly what the punishment is.

Belief in the risk of detection. They must think there is a real chance of being caught, since a penalty that will never be applied costs nothing.

Capacity to act on the calculation. They must be in a state in which the calculation can operate, which excludes offences committed in rage, under intoxication, under compulsion, or by the very young.

Alternatives. A person with no lawful means of subsistence is not choosing between two options in the way the theory requires.

The three variables

The expected cost of an offence is the product of three things, and the ranking between them is the most useful thing in this chapter.

Certainty, the probability of being caught and convicted.

Severity, the size of the penalty.

Celerity, the speed with which it follows.

Bentham's own conclusion, and the modern evidence agree. Certainty matters most. A modest penalty that is very likely deters better than a heavy one that is unlikely, because the offender's expected cost is severity discounted by probability, and the probability of detection for most offences is low. This has a direct practical consequence in India, where conviction rates for many offences are low and delays are long: raising sentences in such a system adds severity to an expectation that is already close to zero, while investment in investigation and in speed changes the multiplier.