as “…people who you would have seen regularly and spent time with in school and outside of school.” The 10 items were: (1) smoked cigarettes; (2) drunk alcohol; (3) got drunk; (4) had problems with alcohol; (5) been in trouble with the law; (6) stole or damaged property on purpose; (7) smoked marijuana; (8) used inhalants; (9) used other drugs like cocaine, downers or LSD; and (10) sold or gave drugs to other kids. The 5 response options were: (1) none; (2) a few; (3) some; (4) most; and (5) all. As an alternate to using raw sum scores and because measurement error and item specific variance are known to produce biased estimates in causal modeling (54) we estimated individual maximum likelihood factor scores for the PGD items at each time point based on the factor loadings and item thresholds calculated under a uni-dimensional factor structure in the Mx (55) software package.
