C. Interrupted Time Series with Comparison Groups: The Effect of Drinking Age Laws and Alcohol-Related Crashes: Time-Series Evidence from Wisconsin

The imposition of a national 21-year minimum drinking age has sparked considerable controversy in recent years. Critics have contended that the perceived "successes" of the increased drinking age are actually due to underlying trends toward fewer alcohol-related crashes among teenagers, and would have occurred in the absence of an increased drinking age. I use monthly Wisconsin time-series data from 1976 to 1993 to estimate the effects of increased minimum drinking ages on alcohol-related crashes involving teenagers. I find that raising the drinking age has resulted in substantially lower alcohol-related crash rates involving teenagers. In addition, I find evidence that crashes increased in years in which Wisconsin's drinking age was lower than those of its neighbors, suggesting that "border hopping" resulted from interjurisdictional policy differences.