Prediction of the risk of male sexual reoffending in Australia

Abstract

This paper reports the findings of a retrospective study designed, primarily, to investigate the predictive accuracy of the Rapid Risk Assessment for Sexual Offence Recidivism (RRASOR); the Static 99 and two models developed in Western Australia, namely the Violent Offender Treatment Program Risk Assessment Scale (VOTPRAS) and the 3-Predictor model on a Western Australian sample of violent and nonviolent sexual offenders. A secondary aim was to establish whether the instruments are equally valid for Indigenous and non-Indigenous, and violent and nonviolent sexual offenders. The data of 538 convicted sexual offenders, who were assessed by the Sex Offender Treatment Program of the Western Australian Department of Justice from 1987 to 2002, were used. The predictor variables were the total scores obtained for each instrument and the outcome variable a conviction in a court for a further sexual offence and, in the case of the VOTPRAS, also a further violent offence. In general the predictive accuracy of the 3-Predictor model was the best, followed by the Static 99, the RRASOR and last, the VOTPRAS. The study provides tentative support for the argument that risk assessment tools that were developed overseas should not be used with Indigenous people without further research and that different assessment tools should be developed for violent and nonviolent sexual offenders respectively.