Investigating treatment change and its relationship to recidivism in a sample of 3773 sex offenders in the UK

This study examines the relationship between psychometric changes in treatment and recidivism in a sample of 3773 sex offenders. All had completed treatment in a prison, between 1996 and 2006. Clinically significant changes were calculated for the psychometrics, and for the overarching psychological problems as represented by the four domains in the Structured Assessment of Risk and Need (Thornton, Sexual Abuse: A Journal of Research and Treatment, 14, 139–154, 2002): (1) sexual interests; (2) pro-offending attitudes; (3) socio-affective problems; and (4) self-regulation problems. Analyses indicate that those whose scores were in the ‘normal range’ before and after treatment were reconvicted at a significantly lower rate than those whose scores were not in the ‘normal range’ after treatment on selected psychometric scales. Additionally, participants who were deemed ‘changed’ overall on three of the four risk domains were reconvicted at a lower rate than those who were deemed not to have changed on these domains. An overall treatment change status was also computed, but this did not add significantly to the predictive validity of a modified version of an actuarial risk assessment tool (RM2000, Thornton et al., Annals of the New York Academy of Sciences, 989, 223–235, 2003) in a Cox regression. The results of the study indicate the potential role and limitations of clinical methodologies in ascertaining whether treatment has worked.