Employing Complier Average Causal Effect Analytic Methods to Examine Effects of Randomized Encouragement Trials

Aims: This article details the application of Complier Average Causal Effect ( CACE) analysis to the examination of youth outcomes from adaptive substance use prevention trials. Methods: CACE analysis is illustrated using youth-reports of tobacco-use from ages 11 to 22, from the Adolescent Transitions Program, a family-focused randomized encouragement trial designed for delivery in the school setting Results: Female gender and early peer deviance predicted family engagement with active intervention components. Further, long-term reductions in youth tobacco use from age 11 to age 22 were found for families that engaged with treatment. Conclusions: CACE modeling techniques enable researchers to examine factors that predict engagement with core intervention components and to examine intervention effects specifically for youth who engaged with those components.