The Clinical Strategies Implementation scale (CSI) was originally designed to be used by external reviewers in order to measure the extent to which evidence-based strategies had been implemented in the treatment of persons with schizophrenia spectrum disorders according to Resource-group Assertive Community Treatment (RACT). The present investigation had two aims: 1) to conduct a revision of CSI and to examine the revised instrument (CSI-R) in terms of interrater reliability (Study I);2) to compare assessments of CSI-R made by experienced assessors with assessments made by students in case management (Study II) in order to determine whether the instrument has validity even when more inexperienced persons are using it. In Study I six raters, who took part in 12 to 15 cases from three outpatient community mental health teams, participated. Results indicated that internal consistency of the CSI-R was strong (alpha = 0.89) as well as correlations between individual raters’ (r between 0.80-0.98). In Study II 91 newly trained RACT praxis trainees participated. Each of them followed one case for eighteen months, i.e., the client which they had been assigned during training (n = 91). The five external auditors in the education program then independently assessed the 91 cases with the CSI-R. Results showed significant correlations between experts and trainees (rho = 0.68, p