We estimated separate sets of analyses for each substance use outcome, and to assure sufficient power, we examined parental knowledge as a time-varying covariate and as a level-2 indicator in separate sets of analyses. The first set of analyses examined intra-individual growth in substance use as a function of parental monitoring as a time-varying covariate at level-1. ηti is the natural log of the ratio of the probability (φ) of using a substance to the probability of not using for adolescent i during time point t.
