Elien Neimeijer

22 Abstract Background: This study examined the psychometric properties of the Group Climate Instrument (GCI) in a sample of N = 189 adults (79%male) withmild intellectual disability or borderline intellectual functioning (MID-BIF) who were residents of a treatment facil- ity in the Netherlands. Method: Construct validity of the GCI was examined by means of confirmatory factor analysis. Also, reliability and convergent validity of the GCI were examined. We also examined the variability in perception of the living group climate between and within living groups by computing intraclass correlations (ICC’s). Results: The model contained four first-order factors: support, growth, group atmosphere, and repression, and a second-order factor overall climate, providing preliminary support for construct validity of the GCI. Reliability coefficients were good for all factors. Prelim- inary evidence for convergent validity was found in significant moderate associations between subscales and single item ratings for the factors of group climate. The ICC’s in- dicated that a considerate proportion of variance can be attributed to between-group dif- ferences. Conclusions: The GCI might be used to assess perception of the living group climate for individuals with MID-BIF in psychiatric and forensic care settings, although further development of the GCI and replication of our findings seem necessary. Introduction There has been an extensive history of research into group climate in (secure) residential settings for more than 50 years (Tonkin, 2015). The notion that psychiatric and correc- tional units have a discernible social climate and the importance of such a climate has been recognised by the World Health Organization (WHO; 1953) and Moos (1975). The WHO stated that climate is ‘the most important factor in efficacy of treatment’ adminis- tered to psychiatric patients in prison and forensic psychiatric hospital settings, includ- ing individuals with intellectual disability (Tonkin, 2015). A therapeutic group climate is essential for effective treatment in residential care (Schubert, Mulvey, Loughran, & Loyosa, 2012). Research shows that the quality of the group climate has a positive influence on the development of clients (Van der Helm, 2011). Transactional processes between sociotherapists and clients and processes be- tween clients make up most of the living group climate within the group (Van der Helm,