The effects of the three-way interaction were probed using a series of conditional main effects tests using techniques recommended by Frazier, Tix, and Barron (2004; i.e., simple effects tests). Specifically, analyses were conducted wherein categorical variables were reverse-coded and continuous variables were re-centered ±1 SD around their mean. This method provides slopes for the association between peer substance use and alcohol use separated by intervention and control participants.
