These ordinal frequency and quantity items were combined to create a single “grams of ethanol consumed per month” alcohol use variable using a method previously reported in Dawson (2000). 1 This involved first converting the categorical response options for frequency and quantity to the midpoints of the range for each option, and then multiplying the product of these conversions by 14 (i.e., Frequency × Quantity × 14). The frequency conversions (shown in parentheses) were based on a month with 30 days and were: never (0), monthly or less (0.5), 2 to 4 times a month (3), 2 to 3 times a week (10.7), 4 or more times a week (23.54). The quantity conversions (shown in parentheses) were: 1 (1.5) or 2, 3 or 4 (3.5), 5 or 6 (5.5), 7, 8 or 9 (8), 10 or more (15.5; the upper bound for this category was defined as 21 to match the upper bound of the continuous alcohol quantity question administered to the first cohort). Participants who responded “0” to the alcohol frequency question were not asked the alcohol quantity question,
