Investigators will implement a multisite randomized controlled trial (RCT) of a family-centered alcohol and drug prevention program for Anishinabe (Ojibwe) pre-adolescents in 3rd or 4th grade (Fall 2017) or who are age 8-10 years on June 1, 2017. to assess its efficacy for delaying and/or preventing adolescent onset of alcohol and drug use. This unique project will empirically address cultural challenges for RCTs involving AI cultures by evaluating contamination and informal diffusion in AI communities and extended families. AI values of sharing and community benefits clash with Western RCT methods of withholding benefits from control groups vs. treatment groups. Although risks of informal community dissemination and control group contamination are widely acknowledged challenges for AI RCTs, the degree to which this actually occurs and the potential impact has never been assessed. Rather, efforts are made to suppress and minimize AI values that result in informal dissemination and contamination, or the potential effects are simply ignored. This research will address these challenges by attempting to measure and control for them. The intent-to-treat study design will allow us to use question routing aimed at identifying content sharing among treatment and control adolescents and their treatment and control group parents. Moreover, the project will also use question routes to investigate potential contamination via extended family members who have contact with both the treatment and control families. Investigators will then assess potential impact of measured contamination on observed intervention effects.