Minimum detectable effect size for main outcomes (accounting for sample
design and clustering)
Power calculations are based on 80% power and a 0.05 Type 1 error probability. Our preferred ICC is 0.06, based on a mid-point of the ICCs for drug use among adolescents documented in Resnicow et a (2010). Our estimates support that the study is well-powered to detect effects of between 4% to 12% improvements in various beliefs, a 3.7pp increase in placement rates, a 3.8pp reduction in dropouts, a 3.7pp increase in attendance, and a 1.7pp reduction in drug use.