NEARI News: Impact of Treatment on Whether a Sexual Offender Will Reoffend

» Posted by on Apr 15, 2016 in Alpha Blog | 0 comments

NEARI News: Impact of Treatment on Whether a Sexual Offender Will Reoffend


The Question

Does sex offender treatment reduce recidivism?

The Research

In 2005, Friedrich Lösel and Martin Schmucker conducted an influential meta-analysis of the

evaluation of sexual offender treatment. This 2015 study provides an update with more recent

primary research and focuses on those higher-quality studies that have comparison/control

Like in

groups as well as documented measures of recidivism rates as a program outcome. After

reviewing more than 3,000 documents, the authors identified 29 studies which included 4,939

(mostly) adult men in treatment and 5,448 men with no treatment. They found that the recidivism

rate for those with treatment (10.1%) was 3.6 percentage points lower than those without

treatment (13.7%) which translates to a 26.3% reduction in recidivism with treatment.

They also identified a number of elements which seemed to produce larger effects. For example,

cognitive-behavioral and multi-systemic treatment programs for adolescents (which takes place in

the community and emphasizes family involvement) seemed to have more positive effects, as well

as adult programs targeting medium to high-risk offenders. Importantly, programs offering more

individualized treatment programs also showed larger positive effects on treatment. Treatment

programs in the community showed a larger effect on recidivism compared to treatment in prison.

Treatment seemed to have a larger impact on adolescents than adults. However, the authors

acknowledge a number of complications in this kind of research. These complications include the

fact that there are very different types of people who abuse, with different ages and developmental

stages, and that sexual offending is a very broad category of crime. Other complications include

that we still know little about the causal factors for this behavior, that there is tremendous variety of

treatment approaches in the field, and finally, the ethical challenges involved in research (e.g.,

leaving some sexual offenders untreated as part a study control group).

The majority of programs in this meta-analysis addressed adult men. Nearly half of the studies

included both men who rape adult women and those who sexually abuse children. No women

were included in these 29 studies and the largest number of adolescents was within the two

studies that explored the impact of MST, which showed the largest treatment effect of any of the


Given the historical focus of the NEARI Newsletter on adolescents, it should be noted that the

results showed a trend that younger boys gained the most from treatment. Findings from this study

indicate that treatment of adolescents is particularly worthwhile and they can also benefit more

from building on the protective factors in their social circles and in their family.

Although the findings are promising, the authors are clear that additional research is needed and

specifically note that there was not enough information on treatment approaches and therefore

this variable could not be adequately tested. The questions noted by the authors were to address

the wide diversity of those who offend and explore what kind of treatment works with whom, in

which situations, and the impact of specific conditions.

Bottom Line: Providing individualized treatment for those who sexually abuse significantly

reduces their risk to reoffend. This effect is particularly strong when working with


Implications for Professionals

Among the many findings in this study, there is one that stands out for professionals at the front

lines: individualized treatment outperforms treatment that is only offered in a group setting. This

group-versus-individual debate has existed for some time. These results suggest that the truly

evidence-based program must be prepared to offer more than one modality or approach and

matches that to the needs and strengths of the individual.

The findings in this study again highlight the importance of understanding that people who

sexually abuse, like abuse itself, appear in many forms. Re-offense rates for adults and

adolescents continue to be different from one another by any measure. It is vital that our programs

(and society’s policies beyond them) take this diversity into account. Age, developmental aspects,

community supports, relationship capacity, and the presence or absence of mental illness can all

play a role in abuse, culpability, and amenability to treatment.

Implications for the Field

There is a certain irony to this study that we should bear in mind. On one hand, we now have

another meta-analysis that tells us that providing treatment to people who sexually abuse can

reduce re-offense; this paper is therefore an important resource. On the other hand, this single

analysis may inadvertently hide the rich diversity of offending and offenders that the public tends

to ignore.

In other words, the study acknowledges the diversity and yet still offers results describing a single

recidivism rate for all who abuse. One wonders whether we are contradicting ourselves by offering

this kind of summary – a single recidivism rate for all sex offenders and giving the wrong message

to the public? After all, a single recidivism rate or effect size can lead to a single image of this

diverse group in the minds of professionals and policymakers alike; an image that is hard to erase

once it is formed.

Clinicians certainly need to understand the data within this meta-analysis. Policy makers need to

understand this data, as well. The authors call for more research that will allow for a more

nuanced approach to these conversations. As mentioned earlier, for clinical practice, the data

supports the importance of an individualized approach for all people who abuse. The ultimate

importance of this study is in its many findings and we caution our field to continue to move

towards a deeper understanding of the population and not just utilize or talk about a definitive

global re-offense rate.


Objectives: Sound evaluations of sexual offender treatment are essential for an evidence-based

crime policy. However, previous reviews substantially varied in their mean effects and were often

based on methodologically weak primary studies. Therefore, the present study contains an update

of our meta-analysis in the first issue of this journal (Lösel and Schmucker Journal of Experimental

Criminology, 1, 117–146, 2005). It includes more recent primary research and is restricted to

comparisons with equivalent treatment and control groups and official measures of recidivism as

outcome criteria.

Methods: Applying a detailed search procedure which yielded more than 3,000 published and

unpublished documents, we identified 29 eligible comparisons containing a total of 4,939 treated

and 5,448 untreated sexual offenders. The study effects were integrated using a random effects

model and further analyzed with regard to treatment, offender, and methodological characteristics

to identify moderator variables.

Results: All eligible comparisons evaluated psychosocial treatment (mainly cognitive behavioral

programs). None of the comparisons evaluating organic treatments fulfilled the eligibility criteria.

The mean effect size for sexual recidivism was smaller than in our previous meta-analysis but still

statistically significant (OR=1.41, p<.01). This equates to a difference in recidivism of 3.6

percentage points (10.1% in treated vs. 13.7% in untreated offenders) and a relative reduction in

recidivism of 26.3%. The significant overall effect was robust against outliers, but contained much

heterogeneity. Methodological quality did not significantly influence effect sizes, but only a few

randomized designs were present. Cognitive-behavioral and multi-systemic treatment as well as

studies with small samples, medium- to high-risk offenders, more individualized treatment, and

good descriptive validity revealed better effects. In contrast to treatment in the community,

treatment in prisons did not reveal a significant mean effect, but there were some prison studies

with rather positive outcomes.

Conclusions: Although our findings are promising, the evidence basis for sex offender treatment is

not yet satisfactory. More randomized trials and high-quality quasi-experiments are needed,

particularly outside North America. In addition, there is a clear need of more differentiated process

and outcome evaluations that address the questions of what works with whom, in what contexts,

under what conditions, with regard to what outcomes, and also why.


Schmucker, M. & Lösel, F. (2015). The effects of sexual offender treatment on recidivism: an

international meta-analysis of sound quality evaluations. Journal of Experimental Criminology.

DOI 10.1007/s11292-015-9241-z.