Predictive validity of the SVR-20 and Static-99 in a Dutch sample of treated sex offenders

In this retrospective study, the interrater reliability and redictive validity of 2 risk assessment instruments for sexual violence are presented. The SVR-20, an instrument for structured professional judgment, and the Static-99, an actuarial risk assessment instrument, were coded from file information of 122 sex offenders who were admitted to a Dutch forensic psychiatric hospital between 1974 and 1996 (average follow-up period 140 months). Recidivism data (reconvictions) from the Ministry of Justice were related to the risk assessments. The base rate for sexual recidivism was 39%, for onsexualviolent offenses 46%, and for general offenses 74%. Predictive validity of the SVR-20 was good (total score: r = .50, AUC = .80; final risk judgment: r = :60, AUC = .83), of the Static-99 moderate (total score: r = .38, AUCD.71; risk category: r = .30, AUC = .66). The SVR-20 final risk judgment was a significantly better predictor ofsexual recidivism than the Static-99 risk category.