Overview of the PROSPER prevention trial’s rationale, methods, and findings

Abstract This chapter provides background for the friendship network investigations presented in this volume by summarizing the PROSPER prevention trial. It discusses the longitudinal trial’s rationale, methods, and outcomes across all study phases, along with its larger family of ongoing studies. The trial’s primary purpose was to refine and test a partnership-based delivery system for sustained, high-quality implementation and dissemination of evidence-based interventions for youth and families. These interventions were designed to reduce youth substance misuse and associated problem behaviors, utilizing the reach of the land grant university Cooperative Extension System linked with public schools. This prevention trial followed participants through early adolescence, adolescence, and emerging adulthood. The wide-ranging and long-term positive outcomes for youth and their families demonstrated—including reductions in prescription drug misuse extending into young adulthood, along with findings on its sustained, quality implementation—suggest its research and public health value. As further chapters of this volume make clear, key indicators of its value also include evidence of positive effects on friendship networks (see Chapter 11), underscoring the benefits of collecting friendship network data in the context of a longitudinal, multimethod measurement prevention outcome study.