Background: Although schools often implement evidence-based sexual health education programs to address sexual and reproductive health disparities, multiple factors may influence program effectiveness. Methods: Using student-reported perceived impact measures as a proxy for program effectiveness, we employed a socio-ecological approach to examine…

Most interventions designed to prevent HIV/STI/pregnancy risk behaviours in young people have multiple components based on psychosocial theories (e.g. social cognitive theory) dictating sets of mediating variables to influence to achieve desired changes in behaviours. Mediation analysis is a method for investigating the extent to which a variable…

Introduction: Group-randomized trials (GRTs) are one of the most rigorous methods for evaluating the effectiveness of group-based health risk prevention programs. Efficiently designing GRTs with a sample size that is sufficient for meeting the trial's power and precision goals while not wasting resources exceeding them requires estimates of the…