The prevalence rates of 5+ binge, 10+ extreme binge, and 15+ extreme binge drinking in the full sample and by gender, race/ethnicity, parental education, geographic region, and population density are shown in Table 1. Of 12th graders, 20.2% reported consuming 5+ alcoholic drinks, 10.5% reported consuming 10+ drinks, and 5.6% reported consuming 15+ drinks in a row at least once in the past 2 weeks. Table 1 shows considerable variation in these rates as a function of the socio-demographic characteristics. Cohort year was negatively correlated with 5+ binge drinking and 10+ extreme binge drinking, but not 15+ extreme binge drinking. Chi-squared tests revealed significant differences (p < .001) by gender, race/ethnicity, parent education, and population density, with one exception; 5+ binge drinking rates did not vary by population density. Pairwise comparisons are shown in Table 1. Below, we consider in more detail socio-demographic differences in a multivariate context with the other covariates. We also examined interactions of all predictors by cohort year; only one out of 60 reached significance of p<.05. This indicates that the associations between predictors and outcomes have remained stable over time.
