Participants responded to items adapted from the Monitoring the Future study (Johnston et al., 2005) that reflect both perceived peer approval and use of substances. Using a response-scale ranging from 1 (strongly disapprove) to 5 (strongly approve) participants were asked to evaluate how their three closest friends would feel if they were to do the following: smoke cigarettes either occasionally or regularly, and drink occasionally, drink regularly, or have 5 or more drinks at a time. Using response options ranging from 1 (none) to 6 (all), participants were also asked to estimate how many of their friends engage in these same behaviors. Approval and use items were standardized and then averaged to form two measures of peer approval/use: cigarettes and alcohol scales. Internal consistencies (Cronbach’s alpha) were 0.87 for alcohol and 0.69 for cigarettes.
