Figure 1. IDEA, role transitions and substance use.

(A) shows the difference in predicted probabilities of past-month marijuana use, and binge drinking, when the 10^th and 90^th percentile IDEA scores are included in computations holding covariates at their mean values. The difference represents the effect of differences in each IDEA subscale on past-month marijuana use, and binge drinking, given the empirical estimates of the logistic regression. An overlapping confidence interval with zero indicates a null result with alpha= .05; and (B) shows the change in predicted probability of past-month marijuana use and binge drinking, with 95% confidence intervals. An overlapping confidence interval with zero indicates a null result with alpha= .002. Estimates were calculated by simulating the first difference in the transition e.g., had a baby from 0 to 1. Each estimate was arrived by the use of 1000 randomly drawn sets of estimates from each respective coefficient covariance matrix with control variables held at their mean values.