After Prohibition, nearly all states restricting youth access to alcohol designated 21 as the minimum legal drinking age (MLDA). Between 1970 and 1975, however, 29 states lowered the MLDA to 18, 19, or 20. These changes occurred when the minimum age for other activities, such as voting, also were being lowered (Wechsler & Sands, 1980). Scientists began studying the effects of the lowered MLDA, focusing particularly on the incidence of motor vehicle crashes, the leading cause of death among teenagers. Several studies in the 1970s found that motor vehicle crashes increased significantly among teens when the MLDA was lowered (Cucchiaro et al, 1974; Douglas et al, 1974; Wagenaar, 1983, 1993; Whitehead, 1977; Whitehead et al, 1975; Williams et al, 1974).
Research findings
A higher minimum legal drinking age is effective in preventing alcohol-related deaths and injuries among youth. When the MLDA has been lowered, injury and death rates increase, and when the MLDA is increased, death and injury rates decline (Wagenaar, 1993).
A higher MLDA results in fewer alcohol-related problems among youth, and the 21-year-old MLDA saves the lives of well over 1,000 youth each year (Jones et al, 1992; NHTSA, 1989). Conversely, when the MLDA is lowered, motor vehicle crashes and deaths among youth increase. At least 50 studies have evaluated this correlation (Wagenaar, 1993).
A common argument among opponents of a higher MLDA is that because many minors still drink and purchase alcohol, the policy doesn't work. The evidence shows, however, that although many youth still consume alcohol, they drink less and experience fewer alcohol-related injuries and deaths (Wagenaar, 1993).
The effect of the higher MLDA occurs with little or no enforcement.
American Medical Association