2 because AO and AI fell within the answer choice “13 to 15.” Reducing concerns about the measurement limitations, analyses examining onset by delay interactions identified no significant interactions in the prediction of the intercepts for heavy drinking or problems. A shorter delay predicted heavier drinking and more problems by senior year of college, regardless of whether AO was early (by age 16 years) or late (after age 16 years). Furthermore, when the models were limited to the earlier AO sample, AO and delay remained significant predictors of heavy drinking and problems. Taken in concert, these results suggest that the lack of measurement resolution for AO and AI at earlier ages did not impact the overall pattern of results.
