Like in Wang et al. (2012), where no main effect of the family-school partnership intervention was found on age of first tobacco cigarette smoked, we did not find a main or interaction effect for the family-school partnership intervention in terms of first marijuana use. Consistent with the explanation we offered in Musci et al. (2015a), the effects of the family-school partnership intervention as reported in prior studies have been less broad and somewhat smaller in magnitude than the classroom-centered intervention effects. One potential explanation for this is the difference in the dose of training and mentoring received by teachers and parents. By design and necessity–given the universal nature of the intervention—parents were only offered 9, 2-hour training workshops focused on parenting, whereas teachers received 24 hours of training and coaching/mentoring in classroom behavior management and instruction throughout the school year. Moreover, only about a 1/3 of the parents attended more than half of the parent training workshops. We are aware of the substantial benefits reported in the literature with respect to family-based substance abuse preventive interventions. However, what is often
