The Fast Track trial was implemented as a multi-site RCT in the early 1990’s to test whether the developmental outcomes of young children at high risk for long-term antisocial behavior could be improved through random assignment to a sustained, multi-component behavioral intervention (CPPRG 1992, 2000). Participants were selected using a multiple-gating screening procedure, resulting in enrollment of 891 children with very high levels of conduct problems at the time of school entry (see Supplementary Figure 1 for design diagram). Written informed consent from parents and oral assent from children were obtained. Parents were paid for completing interviews, and intervention-group parents were paid for group attendance. All procedures were approved by the Institutional Review Boards of participating universities.
