A cross-study contextual analysis of effects from individual-level drinking and group-level drinking factors: a meta-analysis of multiple longitudinal studies from the collaborative alcohol-related longitudinal project.

In contextual (cross-level) analysis within multiple longitudinal general population studies, individual-level drinking behaviors (quantity per typical occasion, frequency of drinking per month and total volume of drinks per month) at final measurement are assessed by three models that simultaneously enter individual- and group-level measures. Two age groups (15-20 and 21-30) are independently assessed. In each model, the Time 1 individual-level drinking behavior and one of three group-level factors are entered. The group-level factors are (1) the percentage of abstainers at Time 1 for each age/sex cohort, (2) the Time 1 group mean for the drinking measure for the age/sex cohort and (3) the mean difference of the age/sex cohort's change in the drinking measure over time. All variables in the model are controlled by variations to exposure in per capita consumption of alcohol during the age/sex cohort's formative years and at Time 2. Meta-analysis assesses the homogeneity of the findings across studies. Models were proposed with the rationale that (1) understanding of individual drinking behavior can be advanced if individual-level data and group-level data are considered in the same models, and (2) integration of these two levels of analyses are, to date, rare. The rationale for using meta-analysis is that findings from the models can be assessed across social contexts with respect to their generalizability. The mean difference model, controlling for individual drinking at Time 1, is the most influential of the group-level models for the younger age group: the degree to which the group changes its drinking pattern is positively related to individual-level drinking behavior at final measurement, over and above the individual's drinking behavior at Time 1, for individual-level frequency of drinking among males (homogeneous among drinkers only). Younger females show more significant relationships for the mean difference females show more significant relationships for the mean difference model. Findings are significant for all relationships examined for the mean difference of the drinking of the group and the individual drinking among the older males and females. Measures of individual-level drinking for all measures at Time 1, controlling for the group-level effects, are significantly related to individual-level drinking at final measurement. The results are homogeneous for quantity (drinkers only) and volume among the young. Findings indicate that characterizations of the drinking for both the individual and the group to which the individual belongs predict measures of drinking practices on the individual level over time.