Assessing change in incarcerated sexual offenders is critical to release decision-making and risk management. This study measured change in a group of treatment completers from a custody-based treatment program. Change was determined through comparison of pre- and post-treatment psychological testing and structured therapist assessment. Data were analysed at the group and individual levels. Multiple complexities were evident when examining the psychometric test results; many participants were considered ‘functional’ (within the normal range) according to extant test norms prior to treatment, and many who were regarded as ‘dysfunctional’ pre-treatment remained in this range post-treatment. Tests measuring constructs from the same risk factor domain often produced inconsistent results and, for most participants, change was only evident on some tests. Psychometric assessment results and therapist ratings were associated. These results highlight the complexities inherent in the evaluation of change. Clinical implications for the measurement of change and test selection are discussed.

Keywords: Sexual offence, Change measurement, Prison, Treatment program.

Vol 2, Issue 2, October 2021