Some notes on the validation of VRS-SO static scores

The present study was a psychometric examination of Violence Risk Scale-Sexual Offender version (VRS-SO; Wong, S., Olver, M. E., Nicholaichuk, T. P., & Gordon, A. (2003). The violence risk scale: Sexual offender version (VRS-SO). Saskatoon: Regional Psychiatric Centre and University of Saskatchewan) static item scores in a Canadian multisite sample of 668 treated adult male sexual offenders. Exploratory factor analysis (EFA) of 13 nonredundant Static-99R and VRS-SO static items generated three factors labelled Youthful Aggression, Sexual Criminality, and General Criminality. The factor and total scores converged with Static-99R and VRS-SO dynamic factor scores. Scores on the VRS-SO static items, EFA-derived factors, and total score each significantly predicted 5- and 10-year sexual, violent, and general recidivism through ROC analyses. Cox regression survival analyses showed all three factors uniquely predicted sexual recidivism to varying degrees in the overall sample; however, only Youthful Aggression and General Criminality uniquely significantly predicted violent and general recidivism in the overall sample and among sexual offender subgroups. Implications for theory, clinical practice, and instrument refinement are discussed.