Involvement with delinquent peers was measured as part of the Peer Behavior Profile (Hirschi 1969) that assesses aspects of the participant's friendship network. It asks the participant to report on how many of their peers are involved in specific activities, and the activities listed cover a wide range of behavior. Responses to an eight-item subscale ask the participant to report what proportion (based on a five-point scale ranging from “almost none” to “nearly all”) of his or her friends are involved in delinquent activity such as stealing, shoplifting, vandalizing private property, staying out all night without permission, run away from home, have been in juvenile court, detained by police, or spent time in jail. The score is the mean value of the eight items for participants aged 12–14 years. The internal consistency for this sample was adequate (Cronbach's α coefficient 0.87).
