Development and validation of a treatment progress scale for personality disordered offenders
Vollm, Birgit A.
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Background: There is a need for a measure to evaluate change in treatment for offenders with a personality disorder, and the Progress Rating Scale (PRS) was developed to meet this need taking account of multiprofessional input.; Method: The PRS comprises six process and five non-process items developed via thematic analysis of routine CPA patient treatment reports at a forensic Personality Disorder Service. Rating for items was fully standardized and operationalized with revisions aiming to maximize inter-rater agreement reflecting good face and content validity. Psychometric properties were examined using PRS ratings for 147 patients at three different time points in conjunction with relevant psychometrics.; Results: Following refinement, the instrument demonstrated good content validity. Intra-class correlations suggested moderate to substantial inter-rater agreement (intraclass correlations: 0.63-0.92). Item analyses indicated good internal consistency for process items (Cronbach's alpha: 0.82-0.88). Correlations with relevant psychometrics revealed meaningful relationships between PRS scores, defence styles and social problem solving. PRS score trajectories were in line with previously known treatment outcomes supporting predictive validity.; Conclusion: The PRS shows promise as process measure in clinical settings but requires further testing on other samples to confirm initial findings and demonstrate its utility.; Copyright © 2015 John Wiley & Sons, Ltd.