To test whether our interaction effects could be attributed to the scale of the alcohol problems measure, we used a log-transformed version of the measure (i.e., log10 (alcohol problems + 1)) in our analyses. The interaction effects trended in the expected direction for parental knowledge and peer deviance, albeit failing to reach significance (unstandardized regression coefficients (b) and p-values (p) for interaction terms: b = 0.51, p = 0.07 and b = 0.30, p = 0.10, respectively). As a set, these supplementary analyses demonstrate that the moderation effects were modestly attenuated after controlling for gene-environment correlation and changing the scale of the alcohol problems outcome variable, but they continued to trend in the same direction and did not entirely go away.
