Changing the legal minimum drinking age: results of a longitudinal study.

Alcohol consumption patterns of samples of college students were examined before and after legislation to raise the minimum drinking age for "weak" beer (3.2% or less alcohol content by weight). Sampling was completed just before and immediately after inception of the law, and then each semester for a total of 4 years. These samples were compared with baseline data obtained 2 years before the legislative action. Quantity and frequency of consumption showed an increase in the sampling period just before the law change and a decrease immediately following. Overall, the quantity-frequency index remained constant, and reports of problem drinking changed very little. Some adjustments were found in drinking locations with students reporting less drinking in public places, such as bars or restaurants, and more drinking in private places, such as residence halls or homes. Policy implications of legislation designed to control drinking are discussed.