Measures of alcohol use frequency varied between and within the 3 samples of interest. Ordinal survey items measuring the frequency of alcohol use were transformed to a pseudo-continuous scale of drinking days per year. Ordinal frequency categories were converted to the median of the described range and rescaled from the original scale of measurement to reflect drinking days per year by multiplying by the corresponding constant (i.e., days per week * 52; days per month * 12). A similar procedure has been used in previous studies to construct pseudo-continuous measures of alcohol consumption (Dawson, 2000; Salvatore et al. 2016; Thomas et al. 2018). The resulting transformed variables have a fixed range of 0 to 365, precluding the inclusion of extreme outlier values. The maximum value was taken for participants who had multiple observations in a single developmental period. A complete description of survey items that were aggregated under each developmental period can be found in Table S1.
