The validity and reliability of the Violence Risk Scale-Sexual Offender version: assessing sex offender risk and evaluating therapeutic change.

The Violence Risk Scale-Sexual Offender version (VRS-SO) is a rating scale designed to assess risk and predict sexual recidivism, to measure and link treatment changes to sexual recidivism, and to inform the delivery of sexual offender treatment. The VRS-SO comprises 7 static and 17 dynamic items empirically or conceptually linked to sexual recidivism. Dynamic items with higher ratings identify treatment targets linked to sexual offending. A modified stages of change model assesses the offender's treatment readiness and change. File-based VRS-SO ratings were completed on 321 sex offenders followed up an average of 10 years post-release. VRS-SO scores predicted sexual and nonsexual violent recidivism post-release and demonstrated acceptable interrater reliability and concurrent validity. A factor analysis of the dynamic items generated 3 factors labeled Sexual Deviance, Criminality, and Treatment Responsivity, all of which predicted sexual recidivism and were differentially associated with different sex offender types. The dynamic items together made incremental contributions to sexual recidivism prediction after static risk was controlled for. Positive changes in the dynamic items, measured at pre- and posttreatment, were significantly related to reductions in sexual recidivism after risk and follow-up time were controlled for, suggesting that dynamic items are indeed dynamic or changeable in nature.