This study examined sex offender risk and treatment change based on a battery of psychometric assessment measures administered to 267 treated adult Canadian federal sex offenders followed up an average 18 years post release. Several significant pre-post changes that were frequently moderate in magnitude (d > .50) were observed across these measures. A factor analysis of the psychometric battery generated three broad need domains consistent with the extant literature that were labelled Socioemotional Functioning, Anger/Hostility, and Misogynist Attitudes. The three need domains and a Need Total, created by their summation, converged with the Violence Risk Scale-Sexual Offender version (VRS-SO; Wong, Olver, Nicholaichuk, & Gordon, 2003) in conceptually meaningful ways and predicted sexual and violent recidivism to varying degrees. Raw measurements of change obtained from pre- to posttreatment frequently bore weak and non-significant relationships to outcome. However, after creating standardised residual change scores to control for pre-treatment score, treatment changes in the individual measures, need domains and Need Total improved significantly in their prediction of reductions in general and sexual violence.
