Again using the bivariate moderation model, we tested for moderation on the A, C, and E components that parental knowledge and alcohol use share. As shown in Table 4, moderation was significant on the cross c path. Therefore, it was not appropriate to use the extended univariate model. Moderation on the unique a, c and e paths were then tested consecutively using the bivariate model. Table 4 shows that the moderating effects on the unique A and E components were retained. Figure 3 shows the changes in the raw variance of the shared and unique A, C and E components as a function of parental knowledge. The genetic and environmental influences decreased under higher scores of parental knowledge and were greatest under lower parental knowledge.
