Esther Mertens

134 | Chapter 6 showed that psychoeducation was related to stronger effects of Social Skills Training interventions. Using didactic instruction might fit better in the school context than using discussion. In a didactic instruction approach, the emphasis is on knowledge transfer between the teacher and the students, whereas a discussion approach is more dependent on the students and the social skills and cohesiveness of the group. Teachers might be less equipped to prevent a discussion from sidetracking than to teach psychological constructs (Horne, Stoddard, & Bell, 2007). Teaching cognitive coping was related to weaker effects on interpersonal competences in general. This finding was somewhat surprising, given that cognitive coping is considered an effective component in other interventions as Cognitive Behavioral Therapy (Yovel, Mor, & Shakarov, 2014) with well-trained therapists (Kobak, Wolitzky-Taylor, Craske, & Rose, 2017). One possible explanation may be that school- based interventions, are often implemented by teachers who only received a short training (e.g., Challen, Machin, & Gillham, 2014) and have no to little experience in teaching cognitive coping. The results concerning structural components showed that longer and more extensive interventions (e.g., involving parents and the whole school) were more effective for targeting system level outcomes such as school climate. Long-term and extensive interventions might be more effective when the intervention aims to increase students’ feelings of safety at school. By targeting multiple systems in which the students are involved (e.g., school, family) teachers and parents might become more sensitive for problems students encounter, such as bullying or problematic relations with peers (Ttofi & Farrington, 2011) and a broad range of risk factors is addressed (Trip et al., 2015). For interventions targeting the individual level such as self-esteem, more extensive interventions were not related to stronger effects nor were less extensive interventions related to weaker effects. Based on these findings, less extensive interventions might be preferred to stimulate the intrapersonal domain due to the easier implementation (Bakermans-Kranenburg et al., 2003), while more extensive interventions may be better suited to stimulate the interpersonal domain. Furthermore, our results showed that components related to stronger intervention effects were not necessarily commonly implemented. For instance, interventions that involved the whole school were related to stronger effects on internalizing problems, bullying and school climate. However, only 10% to 19% of the included interventions involved the whole school. In contrast, some components that were related to weaker effects are implemented more often. For example, teaching emotion regulation, included in 40% to 53% of the interventions, was related to weaker effect sizes on the intrapersonal domain in general, self-esteem, and bullying. Our frequency counts of components are in line with the frequency count by Boustani and colleagues (2015) of effective school-based interventions. These findings indicate that it is important to critically consider which components to include in an intervention and to not simply “do what previously has been done.”