The effectiveness of assessment instruments in measuring change in persons with an intellectual disability who have sexually offended

Abstract

The present research was designed to examine a set of assessment measures for their effectiveness in evaluating risk and treatment needs in a small sample of intellectually disabled sex offenders (IDSOs). IDSO assessment and treatment is a developing field in terms of research and practice. Many of the current assessment measures and treatment models used to date have been based on models for the non-ID offender population (Lambrick, 2003). Measures included in the present study were: the Rapid Risk Assessment for Sex Offender Recidivism (RRASOR), STATIC-99, the Sexual Violence Risk - 20 (SVR-20), the Assessment of Sexual Knowledge (ASK), the Questionnaire on Attitudes Consistent with Sex Offending (QACSO), and the Assessment of Risk and Manageability of Intellectually Disabled IndividuaLs who Offend - Sexually (ARMIDILO-S). A within-subject pre-post design was utilised, with participants acting as their own controls. Participants were assessed on all measures in the pre-treatment phase, and on the SVR-20, ASK, QACSO and acute items of the ARMIDILO-S in the post-treatment phase. Treatment involved engagement in a SAFE-ID group (modelled on the SOTSEC-ID treatment program) over a 7 month period. Although the sample was small, some changes in risk-relevant variables were found. Expected changes were found with the SVR-20, ASK and the client and environmental protective factors of the ARMDILO-S. Unexpected changes were found with the QACSO and the client and environmental risk factors of the ARMIDILO-S. Further research is suggested, including the use of a larger sample.