General deterrence raises some of the oldest questions in criminology. A general deterrent effect would occur where a disposal makes other potential offenders less likely to offend. General deterrence is said to depend on three main factors which have been explored in recent research published by the Sentencing Council:
- the certainty that an offender will be apprehended and punished;
- the speed of that process;
- the severity of the punishment imposed.
Despite pervasive “common sense intuitions”, the evidence for a general deterrent effect related to sentence severity is weak.
A caveat to note is the difficulty of researching the general deterrence effects of sentence severity directly.
Consequently, commentators will not go as far as saying there is no possibility of a general deterrent effect linked to sentence severity: whether given in real cases or provided for in [sentencing] guidelines.
However, based on a literature review, there is no strong evidence to support more severe sentences on the basis of their general deterrent effects.
Moreover, it is noted that some have argued it is time to accept that sentence severity has no effect on the level of crime in society.
There are several reasons why general deterrent effects would seem unlikely to materialise from severe sentences. Notably, a range of evidence on human behaviours and decision-making lends credence to the idea that certainty of punishment is likely a much stronger driver of deterrence than severity. Andrew Ashworth (2019) has identified four “complications” that help to explain this finding. All four are related to a potential disconnect between the objective risks of (re)offending and offenders’ subjective perceptions of that risk.
First, a severe sentence can only have a deterrent effect if offenders know about and understand it. However, a recent review of research on defendants’ understanding found that “very little is known about the extent to which those being sentenced understand the process and the likely sentencing outcome” and that “the limited empirical research in this area suggests that defendants may have limited understanding.”
Second, either a real or perceived low risk of detection by authorities will undermine any deterrent effect.
Third, deterrence-based policies assume that offenders make at least broadly rational decisions, “giving some thought to benefits and costs”, whereas research shows that a myriad of psychological and situational factors mean that would-be criminals very often depart from normatively rational behaviour. For example, offenders have been found to exhibit low selfcontrol, high impulsivity, steep temporal discounting (underweighting consequences further in the future), and other neurocognitive deficits.
In addition, many crimes (in particular, violent, sexual, and drug-related offences) are commonly committed impulsively, using primarily intuitive, ’hot’ cognition driven by emotional arousal (e.g. anger, passion, fear), influenced by simple cognitive rules of thumb or ‘heuristics’ that can cause bias of various kinds and make offending behaviour more likely, and/ or committed under the influence of drugs or alcohol.
In these circumstances, the immediate benefits of criminal behaviour far outweigh any effect of an uncertain legal sanction in the far-off future.
Fourth, the relationship between sentence severity and reoffending will be weak if an offender views other, non-legal costs as more important than a potential legal sanction. Relevant social factors include peer-group influence and fear of lost respect or social standing.
Finally, even in situations where certainty and speed are strong enough for severity to exert an influence (an atypical situation for many offences), the strength of this influence is unclear. Severity, combined with certainty and speed will only tip the balance away from offending beyond a certain threshold. Locating such thresholds is likely to be an extremely challenging task. Given the relatively minor nature of most offences, for many the threshold may be met simply by the fact of a criminal conviction and/ or the stresses of being prosecuted.
Therefore, more severe sentences may have little deterrent effect for many high-volume crimes even where the likelihood of punishment is high. Furthermore, there is evidence that an offender’s sensitivity to harsher penalties in terms of time begins to decrease as the total sentence length increases – meaning the deterring impact gradually diminishes.