Best-practice guidelines for positive psychological intervention research design

Positive psychological interventions (PPIs) have been subjected to considerable criticism in recent years. Following similar movements across other domains of psychology, attempts to replicate classic PPI studies have failed or have produced mixed results. Such failures are often justified with arguments that invoke the complexity of human nature, the influence of contextual factors (for example, hidden moderators) that may arise in different populations, poor evaluation frameworks, or humans being reactive in PPIs and, as a result, modifying their behavior when observed. However, without replicability and consistency in results over time, the validity of PPIs will remain questionable in the broader scientific community unless acted on. In this chapter, it is argued that the lack of replicability and poor effectiveness of PPIs are a function of problems occurring in five areas: (a) intervention design, (b) recruitment and retention of participants, (c) adoption, (d) issues with intervention fidelity and implementation, and (e) efficacy or effectivity evaluation. This chapter focuses on the problems associated with each of these areas and presents general (albeit brief) best-practice guidelines for PPIs, inspired by recent developments in intervention methodology