Elien Neimeijer

15 2009). Clients should be able to use what they have learned in everyday situations to help maintain development and positive change in their lives (Wampold, 2019). Effective treatment is highly context-dependent and the quality of staff-client relationship (ther- apeutic alliance) shapes treatment outcomes more strongly than treatment methods or specific psychotherapy techniques (Asay & Lambert, 1999; Davis, Garske, & Martin, 2000; Hachtel et al., 2019; Luborsky et al., 2002). As individuals within secure forensic care spent most of their time on their living group, apart from work and educational activities, individual and group therapy sessions and leisure activities, group climate is assumed to exert a substantial influence on the effectiveness of treatment. Trieschman, Whitakker and Brendto already referred to ‘the other 23 hours’ in 1969. Group Climate It has long been recognised that group climate plays an important role in the effica- cy of treatment in secure (forensic) settings (World Health Organization, 1953). Group climate was found to be related to motivation for treatment, treatment engagement, treatment satisfaction, therapeutic alliance (Bressington, Stewart, Beer, & MacInnes, 2011; Johansson & Eklund, 2004; Long et al., 2011; Van der Helm, 2011), better wellbeing and mental health (Van Ginneken, Palmen, Bosma, & Sentse, 2019), treatment dropout and dismissal (Beech & Hamilton-Giachritsis, 2005; Moos, Shelton, & Petty, 1973), and reduced levels of aggression and recidivism (Auty & Liebling, 2019; Schubert, Mulvey, Loughran, & Losoya, 2012; Van der Helm, 2012). Group climate is a complex and multi- factorial construct with a lack of conceptual clarity around the components and factors that influence group climate (Van der Helm, 2011). In both research and clinical practice, the range of theoretical perspectives of group climate and lack of a shared definition has led to a somewhat fuzzy concept (Doyle, Quayle, & Newman, 2017; Tonkin, 2015). In this thesis we will use the term group climate, referring to the definition of Stams and Van der Helm (2017, p. 1065): ‘the quality of the social and physical environment in terms of the provision of sufficient and necessary conditions for physical and mental health, well-be- ing, contact and personal growth of the residents, with respect for their human dignity and human rights, as well as (if not restricted by judicial measures) their personal autonomy, aimed at recovery and successful participation in society’. Within secure (forensic) care settings, group climate can vary from closed and