Study shows post-release supervision reduces reoffending

Over the past few years, criminal justice systems across the UK have come under growing scrutiny as rising prison populations have placed sustained pressure on already stretched prison services. With overcrowding becoming an increasing problem, there has been growing interest in the role of community-based alternatives to time spent in custody, and whether they can better support long-term reductions in reoffending. 

For those responsible for sentencing policy and the management of offenders, this is a complex balancing act, requiring difficult choices between public protection, rehabilitation, and reintegration. While imprisonment prevents further offending in the community for the duration of the custodial spell, this effect may be short-lived without effective rehabilitation and reintegration, with incarceration merely delaying offending.  

If community-based supervision is to play a larger role in sentencing, it is essential to understand how effectively it works. Yet there is relatively little robust evidence on its impacts, particularly in the UK.  

Work by researchers in the Department of Economics and Fraser of Allander Institute (funded by ADRUK¹) are seeking to help fill this gap in our knowledge by exploring the impact of post-release supervision on the reoffending outcomes of short-sentenced prisoners.  

This article explains the research and key findings. If you’re interested in listening to a podcast on our findings, you can hear two of the researchers from the project discuss this work here. The academic paper underpinning this work is also available as a discussion paper here. 

What does community supervision entail? 

Offender supervision in the community can take various forms depending on who it applies to. For some offenders, it is a direct alternative to custody; for others, it is part of their post-custody sentence.  

This research focuses on post-release supervision of short-sentenced prisoners, who are a subset of those under community supervision. These people were subject to licence conditions, a type of supervision model for prison leavers that entails periodically meeting with a probation officer and having restrictions placed on one’s liberties.  

Licence conditions can include restrictions on where one can go, who they can interact with and obligations to attend certain programmes/activities. In some cases, it can include drug testing or an electronic tag.  Violating these conditions often results in a prison recall. At the time of our study, this was typically for 14 days.  

What data did we use? 

We used administrative data provided by the Ministry of Justice that covers virtually all individuals in England and Wales who appeared in court, prison or within the probation system at any point between 2011 and 2023. 

The data is de-identified but linked, meaning we can follow offenders’ journeys through the criminal justice system: from court, to prison, to probation, to (if applicable) reappearances in court and/or prison. 

If you want to learn more about the data, please see here.  

How did we estimate the effectiveness of supervision? 

Understanding the causal effect of community supervision on reoffending is not straightforward. Sentences depend on the characteristics of the offender and the offence, as does the length of time that someone is subject to supervision if they are judged suitable for it. This means that comparing the reoffending of those who receive lots of supervision to those who receive little, or no, supervision is not in itself a particularly useful comparison.   

In this research, the causal effect of supervision is derived from a policy change that happened in 2014, specifically the passage of the 2014 Offender Rehabilitation Act (ORA). The ORA introduced 1 year’s worth of post-release supervision for everyone sentenced to less than 12 months custody in England and Wales for an offence committed on or after 1 February 2015. Prior to ORA, people given equivalent sentences did not receive any community supervision after their custodial spell.  

This creates a ‘discontinuity’ in sentencing between those who committed their original offence just before 1 February 2015 (“control group”) and those who committed their offence just after this date (“treatment group”). Intuitively, these two groups should otherwise be the same, but because of which side of this cut-off their offence took place, they are subject to a different ‘treatment’, namely community supervision.  

This assumption can be tested statistically, and the data substantiate this: the control and treatment group exhibit an all but identical criminal history and demographic profile. Put differently, comparing these groups truly constitutes an apples-to-apples comparison. 

What does the analysis show?  

Post-release supervision and licence conditions reduce reoffending  

Prison leavers were significantly less likely to reoffend while under supervision. Within the first four weeks of release, they committed 14% fewer offences than unsupervised offenders and were also 10% less likely to commit any reoffence at all.  

The size of the effect shrank as we expanded our follow-up window. One year after release, the supervised treatment group committed 8% fewer offences than the unsupervised control group. This effect remained persistent even after supervision ended.   

Supervision works best for first-time prisoners  

The benefits of supervision were particularly pronounced for individuals experiencing their first spell in prison. In the first four weeks following release, first-time prisoners were 20% less likely to reoffend as a result of supervision. By contrast, for those with prior experience of imprisonment, the reduction was closer to 6%. 

Importantly, this effect endured over the longer term, with first-time prisoners remaining 5% less likely to reoffend three years after release. No comparable long-term benefit was found for those with prior custodial sentences. 

Prison recalls lead to prolific offenders committing fewer crimes  

An important feature of the supervision regime is the use of licence conditions, where breaches can result in short prison recalls, typically lasting up to 14 days. Nearly a quarter of prolific offenders in the study, defined as individuals with more than five previous prison spells, experienced at least one recall.  

Reoffending among this group fell most sharply during periods when recall activity was highest, suggesting that short-term incapacitation plays a key role in reducing crime for prolific offenders.  

In contrast, recalls were rare among first-time prisoners, indicating that their reductions in reoffending are more likely to reflect genuine behavioural change rather than temporary removal from the community. 

Effects of supervision differ by offence type  

Reductions in reoffending were strongest for less serious offences, such as theft, and offences that do not result in re-incarceration. There is little evidence that supervision reduced serious offences that lead to further prison sentences. This suggests supervision is most effective at preventing frequent, lower-level offending rather than the most serious crimes.  

 More intensive supervision is more effective  

Prisoners on relatively longer sentences (e.g. 6-12 months) received more intensive supervision. These individuals showed larger and more persistent reductions in reoffending than those whose supervision was less intensive. This suggests that the intensity and structure of supervision matter, not just whether it is imposed.  

Supervision more than pays for itself 

A cost-benefit analysis suggested that every pound spent on supervision avoids more than £2 in crime-related costs, including policing, court time and victimisation.  

Explore how supervision affects reoffending

The dashboard below visualises how supervision affects reoffending by week since prison release. Interact with the buttons on the left-hand side to see how these effects change by offender characteristic. Click the bottom right button to open the dashboard in full screen mode.

 

Key takeaways 

• Post-release supervision reduces reoffending in both the short and long run. Individuals subject to supervision commit fewer offences after release than comparable prison leavers who are not supervised, with effects that persist beyond the formal supervision period. 
• Intensity and structure matter. More intensive supervision immediately following release is associated with larger and more sustained reductions in reoffending, highlighting that how supervision is delivered is as important as whether it is imposed. 
• Supervision is most effective for first-time prisoners. The largest and most enduring reductions in reoffending are observed among people experiencing their first spell in custody, suggesting that supervision can support lasting behavioural change when applied early. 
• Different mechanisms appear to operate for different groups. For prolific offenders, short-term reductions in reoffending are closely linked to the use of recalls following breaches of licence conditions, pointing to temporary incapacitation as an important driver. For first-time prisoners, reduced reoffending occurs largely without recalls, indicating more substantive changes in behaviour.

Taken together, these findings suggest that post-release supervision can play a meaningful role in reducing reoffending, particularly when it is well-designed, targeted, and applied at the right point in an individual’s criminal justice trajectory. As policymakers continue to grapple with overcrowded prisons, understanding what makes community supervision effective will be increasingly important. 

[1] Markus Gehrsitz is an ADRUK Research Fellow.