The data presented in this article are from Project Alliance, an ongoing longitudinal study in a large city in the Pacific Northwest. The sample and methodology have been described in detail in other publications (Dishion and Kavanagh 2003; Dishion et al. 2002, 2003). In brief, participants were recruited from the entire population of 6th grade students in three public middle schools in an ethnically diverse metropolitan community. A total of 998 children and their families completed the initial assessment in the 6th grade (that is, 90% of the targeted population). Of those, 997 provided data at least once over the next 3 years (7th, 8th, and 9th grades); 803 provided data in the 11th grade; and 880 provided data at least once over the two assessments that took place in early adulthood (the first one was completed at an average age of 22 years and 3 months, SD = 7.5 months, and the second at age 23 years and 4 months, SD = 7.8 months). In Grade 11, 72.2% of participants brought a friend in our laboratory to participate in
