Background: There are few established methods for the integration of findings from quantitative and qualitative systematic reviews of interventions. This paper describes a method of overarching synthesis that we developed to bring together the findings from four systematic reviews about the effectiveness and experience of school-based interventions for attention-deficit/hyperactivity disorder (ADHD).
Methods: We approached the synthesis from two perspectives:
1. we brought together the findings of two qualitative syntheses using an inductive approach to identify the contextual elements that might influence the effectiveness of interventions;
2. we worked deductively from quantitative findings about the effectiveness of interventions and moderators of effect, to identify findings in our other reviews that offered hypotheses about the relationships between possible moderators and effectiveness.
Results: Findings from the inductive approach revealed a hierarchy of contextual levels that influence the use of school-based interventions. Implications for the development and evaluation of school-based ADHD interventions were raised from the deductive findings which helped to further our understanding of potential moderators of effectiveness. Unlike existing methods of overarching synthesis, the methods employed did not only explain the findings of the effectiveness review, but rather developed a greater understanding of the use of ADHD interventions in school settings.
Conclusion: The addition of an overarching synthesis to this series of systematic reviews has allowed comparison across all reviews, and brought together a breadth of evidence regarding the use of ADHD interventions in school settings. The identified links between reviews are valuable because of their relevance to future intervention programme design and evaluation.