Impact evaluation of the prison-based Core Sex Offender Treatment Programme
Ministry of Justice Analytical Series 2017
Summary
Summary
Aims and background
The aim of the research was to extend the evidence base on the effectiveness of treatment for sexual offenders. This study measures the impact of the prison-based Core Sex Offender Treatment Programme (SOTP) on the re-offending outcomes of sex offenders in England and Wales, whilst controlling for the different observable characteristics, needs, and risk factors of offenders.
Core SOTP is a cognitive-behavioural psychological intervention designed by the HM Prison and Probation Service (HMPPS) for imprisoned men who have committed sexual offences. The Programme is intended to reduce sexual reoffending amongst participants by identifying and addressing known criminogenic needs. It was accredited for use in prisons in 1992 by the then HM Prison and Probation Service Prison and Probation Services Joint Accreditation Panel, which later became the Correctional Services Accreditation and Advice Panel (CSAAP). The CSAAP help the MOJ and HMPPS to develop and implement high quality offending behaviour programmes and promote excellence in programmes designed to reduce reoffending. Programmes are assessed against a set of criteria derived from the “what works” evidence base. These include having a clear model of change, effective risk management, targeting offending behaviour, employing effective methods, ensuring relevance to individual learning styles, and maintaining the quality and integrity of delivery. Changes have been made to the targets, the content, and the methods used in Core SOTP since its introduction in response to emerging research. As a result, during the course of this study (and in the period thereafter) the Programme has changed. However, it remains a cognitive behavioural group based treatment approach. It was, and remains, available in approximately one-sixth of male prison establishments in England and Wales and is intended for individuals sentenced to 12 months or more, who had either a current or previous (sentence) sex offence, were willing to engage in treatment, and were not in denial of their offending.
There were 2,562 convicted sex offenders who started treatment under the prison-based Core Sex Offender Treatment Programme between 2000 and 2012 in England and Wales. These were matched to 13,219 comparison sex offenders using 87 matching factors from Police National Computer (PNC) records, SOTP treatment records, and the Offender Assessment System (OASys) database (where available). Standardised mean differences between the matched treated and comparison groups for the matching factors showed that the matching quality achieved was excellent.
Propensity score matching (PSM) was used to match sexual offenders who participated in Core SOTP (treated sex offenders) to similar sexual offenders who did not. PSM is a statistical matching technique which uses factors theoretically and empirically associated with both receiving the treatment and the outcome variable (i.e. reoffending) to predict a ‘propensity score’, which represents the likelihood of entering treatment. This propensity score is then used to match treated individuals to comparison offenders who are similar to them.
The matched treatment and comparison groups were then compared on an extensive range of proven reoffending outcomes (sexual and non-sexual). These outcome measures were calculated over a period of up to 13.9 years (average of 8.2 years) starting from each offender’s release from prison between 2002 and 2012, with the follow-up period finishing in October 2015. For all individuals in this study (the treatment group plus the unmatched comparison group), the binary reoffending rate for all offences was 38.3% and the sexual reoffending rate excluding breaches, was 7.5%. These are low when compared to international studies but are within the range of other UK-based studies on reconviction rates for sex offenders (Craig et al., 2008).
PSM can provide a robust quasi-experimental approach, although offenders can only be matched on observable variables. While extensive efforts were undertaken in identifying relevant factors, it is possible that unobserved factors could influence the findings that emerge from this research. Such factors include deviant sexual interest, general selfregulation problems and the degree of violence associated with the current sexual offence.
Key findings
Key findings
The main findings of the analysis were as follows:
- Some statistically significant differences were detected over an average 8.2 year follow up period. They were small in magnitude although they widened over the follow-up period. In particular:
- More treated sex offenders committed at least one sexual reoffence (excluding breach) during the follow-up period when compared with the matched comparison offenders (10.0% compared with 8.0%).
- More treated sex offenders committed at least one child image reoffence during the follow-up period when compared with the matched comparison offenders (4.4% compared with 2.9 %).
- Otherwise, the matched treated and comparison groups had similar reoffending rates across a variety of outcome measures.
- A variety of sensitivity analyses were performed, which mostly focused on the sexual reoffending measure. The sexual reoffending treatment effect was found to be reasonably stable across these.
- As previously noted, it is possible that these results could be materially influenced by unobserved factors. However, such factors would need to increase both the odds of treatment and the odds of reoffending after controlling for the observable factors that were included within the matching process. In fact to conclude that the sexual re-offending treatment impact is not statistically significantly different from a reduction of 2 percentage points, the odds of treatment and re-offending would both need to increase by 122%. This increases to 219% for a 5 percentage point reduction. While the sensitivity analysis, involving both treatment and comparison groups, shows reoffending rates to be higher for individuals who have higher risk profiles, the matching process includes a range of factors that are used to determine risk.
The results suggest that while Core SOTP in prisons is generally associated with little or no changes in sexual and non-sexual reoffending, there were some statistically significant differences. The small changes in the sexual reoffending rate suggest that either Core SOTP does not reduce sexual reoffending as it intends to do, or that the true impact of the Programme was not detected.
This study draws on large treatment and comparison groups, long follow-ups, and many matching factors, thus addressing the most common shortcomings in the research field on sex offenders' reoffending behaviour. However it still has a number of limitations that could either bias the findings or the interpretation of them. In particular:
- It is impossible to conclusively rule out the absence of variables relating to deviant sexual interest, general self-regulation problems and the degree of violence associated with the current sexual offence that could possibly influence the results. Moreover, it is possible that the available data do not fully account for issues such as motivation to address offending behaviour. However, these absences are at least partly accounted for by matching factors included in this study (e.g. sexual deviancy by matching factors covering previous offending). Furthermore as shown above, what remains unaccounted for would need to have strong relationships both with participation onto treatment and reoffending to conclude that Core SOTP is associated with a reduction in sexual reoffending.
- The estimated impact of Core SOTP was found to be similar when removing from the comparison group those who were identified as having done community SOTP. However, it will include some differences between the matched treatment and comparison groups that reflect changes occurring after the prison sentence has commenced and which are not associated with the provision of Core SOTP. Such factors include participation on other treatment programmes in prison and in the community, differences in offender management and in supervision, and regional demographics e.g. in employment rates.
- Availability of good quality data on all factors which determine an offenders’ participation on core SOTP, was also a particular issue. It is possible that paucity of data on some key offender characteristics including denial of offending, and a degree of self-selection, could bias the results.
This study does not reveal the extent to which Core SOTP reoffending outcomes are due to treatment design or poor implementation. However the treatment approach should be modified in line with the latest evidence base, of which this study is part. In particular, it could include individual sessions as well as group sessions. It could also focus more on factors that have been established to predict reoffending.
Whilst this research uses a recognised evaluation methodology, a randomised control trial could more robustly estimate the impact of any subsequent programme and this should be considered for the future.
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There's little doubt that the MoJ and HMPPS have a highly-developed default policy of trying to bury bad news and the latest blog post by Frances Crook of the Howard League gives the context:-
The end of sex offender treatment programmes
A few weeks ago I discovered that the prison service had quietly abandoned sex offender treatment programmes.
These courses have been a mainstay of dealing with men convicted of a range of sex crimes and have been a prerequisite for securing transfer to open conditions and eventual release from prison. Tens of thousands of men have gone through the programmes. Now, after two decades, research apparently indicates that the programmes make reoffending more likely.
Our lawyers started to get wind of the change when the young people we represent in prison told us what was happening. I tweeted about it because I wanted to find out what anyone else knew as there had been no announcement. There was only gossip.
I visited a prison and asked the governor and psychologist what was happening. I was told that the programme was indeed being ditched and that new courses were being introduced, that were ‘accredited but not evaluated’. So once again, something that seems to be a good idea is going to be imposed on people despite the fact that no one has any idea whether it will make things better or worse.
The Mail on Sunday journalist, David Rose, picked up the story from my tweets and did some investigating, and an article was published on Sunday.
I have always been sceptical about prison-based offender courses. Whilst I appreciate they get people out of their cells for a few hours, and goodness knows that is a good thing, how much they really change attitudes or behaviour is a moot point.
Of course, in a prison like Grendon where the whole institution is focused on therapy and engaging people, it is well known that lives are changed and success pretty much guaranteed. However, a prisoner doing a few hours a week on a behaviour programme, whilst living in a fetid, violent, unpredictable, drug ridden, filthy prison and being treated with little respect the rest of the time, seems to be to be asking a lot.
It is disappointing nevertheless that not only do they not help but the sex offender courses appear to make things worse.
Prisons are odd places, not like real life in any way. I tend to think that expecting any behaviour courses in prisons to prevent future offending or to work magic and turn men with a history of violence, aggression and misogyny into model citizens is just not going to work.
These courses have been a mainstay of dealing with men convicted of a range of sex crimes and have been a prerequisite for securing transfer to open conditions and eventual release from prison. Tens of thousands of men have gone through the programmes. Now, after two decades, research apparently indicates that the programmes make reoffending more likely.
Our lawyers started to get wind of the change when the young people we represent in prison told us what was happening. I tweeted about it because I wanted to find out what anyone else knew as there had been no announcement. There was only gossip.
I visited a prison and asked the governor and psychologist what was happening. I was told that the programme was indeed being ditched and that new courses were being introduced, that were ‘accredited but not evaluated’. So once again, something that seems to be a good idea is going to be imposed on people despite the fact that no one has any idea whether it will make things better or worse.
The Mail on Sunday journalist, David Rose, picked up the story from my tweets and did some investigating, and an article was published on Sunday.
I have always been sceptical about prison-based offender courses. Whilst I appreciate they get people out of their cells for a few hours, and goodness knows that is a good thing, how much they really change attitudes or behaviour is a moot point.
Of course, in a prison like Grendon where the whole institution is focused on therapy and engaging people, it is well known that lives are changed and success pretty much guaranteed. However, a prisoner doing a few hours a week on a behaviour programme, whilst living in a fetid, violent, unpredictable, drug ridden, filthy prison and being treated with little respect the rest of the time, seems to be to be asking a lot.
It is disappointing nevertheless that not only do they not help but the sex offender courses appear to make things worse.
Prisons are odd places, not like real life in any way. I tend to think that expecting any behaviour courses in prisons to prevent future offending or to work magic and turn men with a history of violence, aggression and misogyny into model citizens is just not going to work.
Frances Crook