What Works to Reduce Reoffending: update of the evidence on imprisonment and community disposals

Glossary

Desistance

The term "desistance" is used extensively in this paper and refers to an extended period of refraining from further offending. However, within the literature there is significant variation in the length of time used to define desistance, with some researchers claiming that 'true desistance' can be determined with certainty only after offenders die. In most evaluations, a two-year follow-up period is used to differentiate desisters from recidivists.

Deterrence

Deterrence refers to the extent to which a sentence/punishment might deter people from offending. Deterrence theory suggests that the more severe the punishment, the greater the deterrent effect. However, in practice this doesn’t consistently apply.

Deterrence can be divided into two categories:

1. General Deterrence – when the existence of a disposal lowers the likelihood of offending across a population due to three elements: certainty of punishment, speed of process, and the severity of punishment.

2. Specific Deterrence – when receiving a disposal lowers the likelihood of a specific person reoffending in order to avoid receiving it again. Though evidence shows that repeat offenders may perceive deterrence differently, based on their own subjective experiences of punishment.

Rehabilitation and reintegration

The terms rehabilitation and reintegration have varied meanings across the academic literature though they are both processes that act as key objectives of sentencing. Upon release from prison, offenders can be considered ‘rehabilitated’ and the processes offenders undergo and their effects, such as sentences or particular programmes, can be termed ‘rehabilitation’. Whereas, ‘reintegration’ represents full entry back into society, which many argue should be a key objective of sentencing and the ultimate aspiration for positive criminal justice outcomes (Sentencing Council 2019).

Reduced Reoffending

Reducing reoffending is a step towards achieving desistance, where desistance refers to an extended period of not reoffending. It is important to note that reduced reoffending might accrue in different ways, which may or may not show up in data, such as reductions in:

• Frequency: for example, income support may reduce someone’s perceived need to shoplift as frequently, but not remove it altogether if they still cannot meet all their costs at the end of the month
• Severity: for example, violence reduction and anger management might mean someone stops carrying a knife and can avoid a physical fight, but may still struggle to contain verbal altercations and threats
• Type: for example, someone may access parenting and mental health support that help them stop perpetrating domestic violence, but continue to commit drug supply crimes because they are reliant on the income

In all of these cases, it would be arguable that the reduction in offending reflects a benefit for society and a desirable outcome – even if it is incomplete – yet they are unlikely to be captured by the simple measures the data allows for.

Additionally, various metrics of reoffending exist in the academic literature and within different criminal justice jurisdictions. For example, in Scotland the focus of official statistics is ‘reconviction’ and reconviction rates are typically based on a one-year follow-up period (Scottish Government 2024). Whereas in Ministry of Justice data in England and Wales, a proven reoffence is defined as “any offence committed in a one-year follow-up period that resulted in a court conviction, caution, reprimand or warning in this timeframe, or a further six-month waiting period to allow the offence to be proven in court.” (Ministry of Justice 2021)

These differences are important to acknowledge, as different methodologies for measuring reoffending rates can also result in different estimates of the effectiveness of interventions and sentencing. Notably, a short follow-up period may overestimate the effectiveness of interventions if there is reoffending that takes places after the follow-up period has ended. Further, looking solely at counting any instance of reoffending but failing to account for a reduction in severity or frequency over time may fail to recognise the progress that an offender has made over the longer term.