Esther Mertens

24 | Chapter 2 Abstract Background: Students following a low education track have an increased risk for developing problem behaviors. Rock and Water is a widespread, but still poorly evaluated, intervention that aims to improve students’ socio-emotional adjustment and social safety. The aims of this study are to evaluate (1) the effectiveness of Rock and Water on socio-emotional adjustment (i.e., psychosocial wellbeing, sexual autonomy, and resilience) and social safety (i.e., perceived social security in the classroom, aggression, and bullying) and to examine (2) moderators and (3) mediators of its effects. Methods: Schools are randomly assigned into four conditions: ‘Light’ (a core team of teachers is trained), ‘Standard’ (a core team of teachers and the whole school team is trained), ‘Plus’ (a core team of teachers, the whole school team is trained, and parents are involved), or ‘Control condition’ (Care As Usual). We aim to include 180 7th Grade students in each condition ( N = 720) across all waves. A multi-informant (i.e., students, parents, and teachers) approach is used to assess the outcomes (socio- emotional adjustment and social safety), moderators (student, trainer, and parent characteristics) and mediators (self-control, self-reflection, self-esteem, and emotion regulation). Video-observations will be analyzed in a subsample to study the possible mediating effect of changes in deviant and prosocial communication among students on the effect on social safety. Discussion: This project will provide information on the effectiveness of (different levels of school and parental involvement in) Rock and Water, which can be used by schools to decide upon the most efficient way to improve the care for the students. We will be able to shed more light on what works for whom and the working mechanisms of Rock and Water. Trial registration: Dutch Trial Registration number 6554, registered on the 3 rd of July 2017. The design of this study was approved by the Ethical Committee of the Faculty of Social and Behavioral Sciences of Utrecht University (FETC17-015). This study is financially supported by a grant from The Netherlands Organization for Health Research and Development, grant number 531001106. Keywords: Rock and Water; intervention; socio-emotional adjustment; social safety; effectiveness; Randomized Controlled Trial