Do State Tobacco 21 Laws Work?

Tobacco 21 (T-21) laws prohibit the sale of tobacco products to individuals under age 21. This study is the first to comprehensively examine the impacts of statewide T-21 laws on youth tobacco consumption, including spillovers to minor teens. Using data from the 2009-2019 Behavioral Risk Factor Surveillance Survey (BRFSS) and a difference-in-differences approach, we find that the enactment of a statewide T-21 law was associated with a 2.5 to 3.9 percentage-point decline in smoking participation among 18-to-20-year-olds. A causal interpretation of our estimates is supported by event-study analyses and falsification tests for young adults ages 21 and older. Next, using data from the 2009-2019 State Youth Risky Behavior Surveys (YRBS), we find that statewide T-21 laws reduced tobacco cigarette and electronic cigarette (e-cigarette) consumption among 18-year-old high school students. However, descriptive evidence suggests that the negative impact of T-21 laws on e-cigarette use among 18-year-olds may be partially blunted by an increase in borrowing e-cigarettes from others. Finally, we find that T-21 laws generate important spillovers including (i) a reduction in tobacco cigarette use among 16-to-17-year-olds, a group that relies heavily on the “social market” — including 18-year-old peers — to access tobacco, and (ii) reductions in both marijuana use and frequency of alcohol consumption among older teenagers.