Elien Neimeijer

25 Measuring group climate repeatedly and giving feedback to professionals working with these clients has been shown to improve group climate but also to increase treatment motivation and empathy and diminish criminal cognitions which can facilitate return to society (Tonkin, 2015). The Group Climate Instrument (GCI) was developed to measure the group climate and has been proven to be a valid and reliable measure in other set- tings such as residential youth care, prisons and psychiatric (forensic) institutions and for different age groups (Van der Helm et al., 2011). The majority of studies however have been undertaken with adolescents, therefore the validity of the GCI with adults (with MID-BIF) is less well established (Bell et al., 2017). To the best of our knowledge, no studies have been published on the psychometric characteristics of the Group Climate Instrument adapted to individuals with MID-BIF in secure treatment facilities. The aim of this study is to examine the psychometric properties (i.e., construct valid- ity, convergent validity and internal consistency) of the Group Climate Instrument (GCI, Van der Helm, et al., 2011) in a sample of individuals with MID-BIF (N = 189) who were residents of a secure treatment facility. As transactional processes between clients and sociotherapists and between clients make up a large part of the climate we propose the perception of the group climate to quality to be most salient in a group level as opposed to individual or facility-level. It is important that changes to working practices are made on the basis of the perspective of clients for which the GCI provides an important tool. Methods Participants The sample of participants consisted of 189 participants, all residents of Trajectum, a (forensic) secure treatment facility for individuals with MID-BIF located in the northern and eastern part of the Netherlands. All 441 residents were invited to participate in the study. In total 208 residents participated (47% response rate). Data of 19 participants (9% of 208) were excluded from the analyses because of missing data of intellectual function- ing (IQ), resulting in a sample of 189 participants. Participants (79% male) were aged between 18 and 69 years ( M = 38.3, SD = 12.9). Of the participants, 44% had a mild ID (IQ 50-69) and 56% had borderline intellectual functioning (IQ 70-85) ( M = 69.8, SD = 8.7). Besides MID-BIF, participants had severe problem behaviour in combination with mental health problems and/or serious problems in all areas of life, often with a history