We also conducted analyses to examine whether adolescent gender and grade level influenced the relationship of parental knowledge to adolescent substance use. Hypotheses were partially supported, such that analyses indicated that gender moderated the relationship between mean levels of parental knowledge and the slope of marijuana use (p = .03), other drug use (p = .02), and any drug use (p < .01) over the one year period (Table 1). Contrary to expectations, however, baseline parental knowledge was a significant protective factor for increases in substance use across one year for boys, not girls. Thus, when boys and girls with equivalent levels of parental knowledge are compared, there is a 16 percent decrease in the slope of marijuana use as well as other drug use and 14 percent decrease in the slope of any drug use for boys when compared to girls. No such moderator effects of mean parental knowledge were found for baseline substance use (i.e., the intercept).
