In the next set of analyses, we estimated growth models to examine the effect of parental knowledge, gender, and the gender by knowledge interaction on the intercept (γ 101, γ 102, γ 103) and slope (γ 111, γ112, γ 113) for a given substance use outcome. The final set of analyses examined the effect of parental knowledge, grade, and the grade by knowledge interaction on the intercept (γ 101, γ 102, γ 103) and slope (γ 111, γ112, γ 113) for a given substance use outcome. All adolescent characteristics were dummy coded so the group coded zero had a relationship between parental knowledge and substance use represented by γ 102 and γ 112, while the relationship for the group coded one was represented by γ 102 + γ103 and γ112 + γ113.
