Consistent with previous research (Marshal and Molina, 2006), deviant peer affiliation was assessed using a measure adapted by Chassin and colleagues (1993) from the Monitoring the Future study (Johnston et al., 1988). Adolescents used a 6-point scale (none to all) to report how many of their friends engaged in six forms of substance use: occasional and regular use of alcohol, marijuana, and other drugs. Adolescents also rated on a 6-point scale how their close friends would feel if they engaged in these six forms of substance use, as well as “weekend heavy alcohol use,” ranging from strongly disapprove to strongly approve. Similar to other studies (Marshal and Molina, 2006), the zero-order intercorrelation between the mean of the peer use items and the mean of the peer tolerance of use items was fairly strong (r= 0.81, p < 0.001), therefore an overall peer deviance score was computed by averaging all items (Cronbach’s α = 0.96).
