Costs and benefits of cooperative learning as a universal school-based approach to adolescent substance use prevention.

Substance use during early adolescence implies a greater likelihood of abuse and dependence in later adolescence or adulthood. In turn, substance abuse and dependence are linked to a variety of maladaptive long-term health-related outcomes that imply significant individual and societal costs. In this paper, we evaluated an approach to substance use prevention that relies on the vital role of peers, who comprise a key risk factor for adolescent substance use. This approach (i.e., cooperative learning, CL) focuses on interrupting the process of deviant peer clustering and providing at-risk youth with the opportunity to build social skills and cultivate friendships with low-risk youth. In addition to testing the efficacy of CL in reducing the number of students who become regular substance users, we also conducted a cost-benefit analysis. Using four waves of data from a cluster-randomized trial (N = 15 middle schools, 1890 students, 47.1% female, 75.2% White, 13.9% of students were receiving special education services), we found that significantly lower percentages of students in the intervention (CL) schools became regular users of tobacco, alcohol, and marijuana. We estimated that the reduction in substance use associated with the implementation of CL resulted in total lifetime benefits of between $1027 and $4621 per student (in 2019 dollars), or between $8.79 and $39.54 for each dollar invested in CL. Benefit/cost ratios would go up to $22.54-$101.39 per dollar invested with the continual implementation of CL, assuming retraining every 5 years. Implications and future research directions are discussed.