Study protocol of a quasi-experimental evaluation of the school-based prevention system Weitblick

Abstract Background This quasi-experimental study is designed to evaluate whether the school-based prevention system Weitblick promotes the adoption of science-based prevention in schools and increases the implementation of evidence-based prevention programmes (EBPs) in schools. In the long run, Weitblick is also expected to change risk and protective factors, reduce the prevalence of adolescent problem behaviour and increase the prevalence of healthy behaviour and well-being. Methods The study follows a sequential design, including approximately 12 schools at six time points, each spaced about six months apart, resulting in a total of 72 schools. Baseline measurements will be conducted at the start of each of the six sequences and schools will begin implementing Weitblick, aiming for full implementation within 12 months. Once fully implemented, the intervention phase begins, with post- and follow-up measurements taken at one-year intervals. On average, five school key informants per school will be interviewed at 12-month intervals, resulting in about 360 key informants per wave (open cohort design). Additionally, the number of EBPs and their reach will be documented every two years. Around 2,300 sixth graders from 43 schools will be surveyed longitudinally at two-year intervals. Outcome changes will be assessed using a three-level model, analysing changes by survey wave (level 1), nested within respondents (level 2), and schools (level 3). Discussion This is the first study to evaluate the effectiveness of Weitblick. We expect that the successful implementation of Weitblick will significantly increase the adoption of science-based prevention, the number of EBPs, and their reach. In turn, this should lead to measurable changes in risk and protective factors, behaviours, and well-being. Trial registration: This study was registered with German Register of Clinical Studies: DRKS00034046 on April 15, 2024.