The Minimum Legal Alcohol Drinking Age. History, Effectiveness, and Ongoing Debate
Minimum legal alcohol drinking age (MLDA) laws provide an example of how scientific research can support effective public policies. Between 1970 and 1975, 29 U.S. Federal States lowered their MLDAs; subsequently, scientists found that traffic crashes increased significantly among teenagers.
Alcohol use among youth is related to many problems, including traffic crashes, drownings, vandalism, assaults, homicides, suicides, teenage pregnancies, and sexually transmitted diseases.
Research has demonstrated the effectiveness of a higher MLDA in preventing injuries and deaths among youth. Despite laws prohibiting the sale or provision of alcohol to people under age 21, minors can easily obtain alcohol from many sources.
Increased MLDA enforcement levels and deterrents for adults who might sell or provide alcohol to minors can help prevent additional injuries and deaths among youth.
Effectiveness of the MLDA
Reductions in Alcohol Use
Following the end of Prohibition, each State developed its own set of policies to regulate the distribution, sale, and consumption of alcohol. In addition to the MLDA, examples of other alcohol control policies include excise taxes, restrictions on hours and days of sales, and server training. Many of these other alcohol policies have only recently been evaluated (see Toomey et al. 1994 for a review of the research literature). Of all the alcohol control policies, MLDA policy has been the most studied. Since the 1970’s, at least 70 studies have explicitly examined the effects of either increases or decreases in the MLDA, with some studies using more robust research designs than others.
MLDA policies may have been evaluated sooner and more often for a variety of reasons, including:
- A growing concern about youth driving under the influence of alcohol;
- Availability of archived, time-series data on traffic crashes;
- The fact that many States first lowered, then raised, their MLDA’s; and
- Preliminary research showing the large effects of changes in MLDA’s.
MLDA laws have been evaluated mostly in terms of how changing the MLDA affects rates of alcohol use and traffic crashes among youth.
When youth consumes alcohol, it is mostly beer. As a result, reduced rates of alcohol use among youth after the MLDA was increased were primarily evident in decreased rates of beer consumption (Berger and Snortum 1985). Rates of wine and distilled spirits use among youth did not change dramatically following the rise in the MLDA (Barsby and Marshall 1977; Smart 1977).
Opponents of the age-21 MLDA theorized that even if a higher MLDA reduced alcohol use among minors, alcohol consumption rates and alcohol-related problems would surge among those age 21 and older. In other words, opponents believed that a “rubber band” effect would occur: When youth turned 21, they would consume alcohol to “make up for lost time” and thus use alcohol at higher rates than they would had they been allowed to consume alcohol at an earlier age. A study by O’Malley and Wagenaar (1991), however, refutes this theory. Using a national probability sample, O’Malley and Wagenaar found that the lower rates of alcohol use due to a high legal alcohol drinking age continued even after youth turned 21.
Although the MLDA’s effect on youth alcohol consumption is important, a key consideration is whether the MLDA ultimately affects the rates of alcohol-related problems.
Alcohol use among youth is related to numerous problems, including traffic crashes, drownings, vandalism, assaults, homicides, suicides, teenage pregnancies, and sexually transmitted diseases. Alcohol use is reported in one-fifth to two-thirds of many of these problems (Howland and Hingson 1988; Plant 1990; Roizen 1982; Smith and Kraus 1988; Strunin and Hingson 1992).
As alcohol use rates increase or decrease, rates of alcohol-related problems may change in response.
Decreases in Traffic Crashes
Using various research methods, at least 50 studies have evaluated the effect of changes in the MLDA on traffic crashes (Wagenaar 1993). Some studies assessed policy changes in only one State, whereas others analyzed the MLDA’s effect across multiple States. These studies evaluated the effect of MLDA changes on a variety of outcomes, including total traffic crash fatalities for youth driving under the influence of alcohol (DUI) convictions; crashes resulting in injuries; and single-vehicle nighttime crash fatalities (the crashes most likely to involve alcohol).
Most studies on the effect of lowering the MLDA found an increase in traffic crashes and traffic deaths among youth (Wagenaar 1993). Of the 29 studies completed since the early 1980’s that evaluated increases in the MLDA, 20 showed significant decreases in traffic crashes and crash fatalities. Only three clearly found no change in traffic crashes involving youth. The remaining six studies had equivocal results.
Based on results from research studies such as these, the National Highway Traffic Safety Administration (NHTSA) estimated that in 1987 alone, 1,071 traffic crash fatalities were prevented because of the MLDA of 21 (NHTSA 1989).
Since 1984 researchers have been investigating whether changes in the MLDA also affect other alcohol-related problems. Of the four studies conducted to date that focused on other social and health consequences of alcohol use, three found an inverse relationship between the MLDA and alcohol-related problems:
A higher legal alcohol drinking age was correlated with a lower number of alcohol problems among youth.
- The New York State Division of Alcoholism and Alcohol Abuse (1984) found a 16% decrease in rates of vandalism in four States that raised the MLDA.
- Smith (1986) found an increase in non-traffic-related hospital admissions following decreases in the MLDA in two Australian states.
- Jones and colleagues (1992) found lower rates of death caused by suicides, motor vehicle crashes, pedestrian accidents, and other injuries in States with higher MLDA’s.
The same arguments used to lower the MLDA 20 years ago are being used today. Despite ongoing debates about the MLDA, research demonstrates the effectiveness of a higher MLDA in preventing alcohol-related injuries and deaths among youth.
As the MLDAs were lowered, rates of injuries and deaths increased; when the MLDA’s were raised, injuries and deaths significantly decreased.
The benefit of using environmental (i.e., external) approaches, such as the MLDA, is further supported by the fact that alcohol consumption rates were reduced even after youth turned age 21.
In contrast, individual approaches (e.g., school-based programs) have generated only short-term reductions in underage alcohol use. This finding suggests that to create long-term changes in youth alcohol use and alcohol-related problems, strategies that change the environment should be used.