In general, deterrence theory in the criminal justice system refers to the belief and practice of how threats or limited force by the State can convince (potential) offenders to refrain from initiating any course of criminal action.

The foundation of the deterrence theory of punishment can be traced back to the work of three modern philosophers: Hobbes (1651), Beccaria (1872) and Bentham (1789). These classical thinkers patronized the concept of severity, certainty and celerity of legal punishment as an antidote to criminal behaviour. They believed that if punishment is severe, certain and swift, a rational individual would weigh potential gains and losses before engaging in illegal activity and naturally be discouraged from breaking the law when the loss is greater than the gain.

Even to this date, severity of punishment is believed to be one of the key deterring elements of the judicial system, and the same is reflected on the existing criminal law of the land, expecting the code to thus encourage law-abiding behaviour amongst the citizens. Certainty of that punishment implies that the sanction is more likely to be implemented against the offender if the crime is committed. Of these three components, severity has often been measured by length of prison sentence and certainty by detection rates or arrest rates. Celerity, i.e. switness of legal sanctions, as a component of deterrence, has rarely been tested empirically. Curiously though, policymakers across the globe commonly assume that access to speedy justice is crucial both for reducing crime and satisfying the interests of victims.

It is expected that increased severity should have the same impact as increased certainty, implying that costly enforcement of the law could be reduced in favour of higher penalties. However, research suggests that the impact of increased severity is ambiguous at best. It is possible that these elements of deterrence cannot be conceptually separated from each other and that their impacts need to be considered as one package (Howe and Brandau, 1988; Mendes, 2004; Mendes and McDonald, 2001). Some of these differences could reflect the variable impact of specific and general deterrence, and in particular, the difference between the experience of punishment and the future prospect of it.

Walters (2015) analyses a framework that suggest that while there is a rational element in most crimes, criminals may react more to proximal rather than distal relationships which is why ‘get tough in crime’ policies does not often work in practice. This may explain for instance why sentencing length may matter less than certainty of detection suggestion that while deterrence can be achieved, it does not quite follow the strictly rational choice model postulated by Becker.

Researchers suggest that the deterrence effect of certainty, severity and celerity be studied separately to derive any practical conclusion. So far, it is observed that the deterrent effect of certainty of legal sanction is more than that of severity of legal punishment.

The principle of deterrence in punishment refers to the effect of punishment in preventing an the particular individual or other potential offenders from committing the same or even similar criminal actions. This reflects the classical thinkers emphasis on free will and rational choice.

This presumption of the deterrence theory begs the following questions:

1. Does a person think rationally while committing a crime?
2. Is the probability of the same punishment being executed the same for all individuals accused of similar criminal behaviour?
3. Is the deterrent effect same across all legal sanctions against all forms of crime?

Intelligebly, the strongest criticism against the deterrence theory is the over-reliance on rational choice. Practically speaking not all human behaviour, if any, is completely rational. Also, no human being makes rational decisions at all times. Besides, as researches have found, several offenders lack the ability to make an accurate assessment of the certainty and/or severity of the punishment but often over-estimate the “benefits” of the crime and therefore consider their choice “worthy”.

It is important to note however that the rational choice theory claims much more than only an explanation of the deterrence theory. The rational choice theory was proposed as a general explanation of not only the decision of an offender to possibly commit a crime, but also an explanation for the desistance from or development of a criminal career.

There also exists a controversy over how to define and measure deterrence. One important notion is the understanding of perceived deterrence. There is the crucial question of how people perceive the legal sanction will work out for them, whether they think they will be caught and even if they will be caught do they think that they will be prosecuted. Perceived deterrence suggests that what people think will happen influences their course of action significantly. The relationship between actual certainty of punishment and perceived certainty of punishment is difficult to measure empirically. Important research findings in the field suggest that actual severity of sanctions is needed to instil perception of certain severe punishment.

Some researchers rightly point out that there are the ideal few of the community who behave in a law abiding ways because they actually believe that it is the right way to behave, and not exactly because they have any extensive knowledge of certain, severe legal sanctions against crimes. This is observed by quite a few scholars. This line of research suggests that citizens may be grouped into acute conformists who are the ideal few as described above, deterrable respondents who could be deterred by punishment and incorrigible respondents who remain unhinged by the notion of legal punishment.

Other research studies also show how little impact the deterrence effect has for habitual offenders and high risk offenders who are way more influenced by the opportunities to commit the offence that they plan and by their respect for criminal activities as a way of life.

Another missing piece in the study of deterrence effect is the lack of research into actual certainty of execution of the legal sanction adjudicated. Not to ignore, the hyper impact that depiction of crime and punishment in the media has over the general population as well as specific offenders.

According to the deterrence theory, there are three types of deterrence:

1. Specific Deterrence: This is the concept that punishing the offender will deter him from re-offending.
2. General Deterrence: The belief that punishing one offender would deter any potential offender in the general population from committing similar offence.
3. Marginal Deterrence: It is the concept that the penalty of a crime may prompt commission of a marginally more severe crime because that crime receives the same magnitude of punishment as the original one.

In another perspective, there’s also the question of short-term deterrence vs long-term deterrence.

Research till date shows inconclusive evidence of the impact of deterrence and dissuasion on the thinking of potential aggressors. We have deterrence by denial strategies, i.e. making it infeasible or more likely for the criminal act to succeed or and these are mostly acts in defence, and deterrence by punishment, i.e. ensuring severe penalties and threats of wider punishments that vastly increase the cost of attack and/or criminal act.

The RAND Corporation reports that most studies suggest denial strategies are inherently more reliable than punishment strategies. This is mostly because the aggressor often doubts how far the authority will follow through with the threats of punishments and even if they do would it be to the same severity as suggested.

An important observation is that punishment may have an immediate but not a long-term deterrent effect on individuals.

In conclusion, three variables of deterrence, also referred to as the three forms of social control, that have the maximum observable influence on criminal behaviour are:

1. Moral commitment which is the internalization of legal norms.
2. Fear of social disapproval.
3. Fear of actual legal punishment.

Note: This article is based on what we have been reading about the topic from various sources and may be updated with increased understanding and learning.

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