Christopher (Kitt) Carpenter and Carlos Dobkin The Effects of Alcohol Access on Consumption and Mortality We thank NIH/NIAAA for financial support R01-AA Comments welcome.

Overview Research Question: What is the causal effect of alcohol consumption on mortality? Regression Discontinuity (RD) design that leverages the minimum legal drinking age (MLDA). We find that the MLDA substantially reduces both alcohol consumption and many types of mortality.

Outline of Talk Motivation & Literature Review Research Design & Data Description Results on Alcohol Consumption Results on Mortality Discussion

Motivation Underage drinking “costs” society $53 billion annually (IOM 2004) –Far more prevalent than tobacco/drug use –Well established link with traffic crashes Less evidence on other types of mortality Governments devote lots of resources to reducing youth drinking & adverse effects –Most direct regulation: MLDA –Particularly relevant now

Why are youths of special interest? The age-profile of drinking and nearly all adverse outcomes (acute mortality, crime, risky sex) peaks at late teens/early 20s  Age-targeted policies can generate meaningful effects on overall outcomes

Relevant Literature MLDA & drinking: panel evaluations –Dee 1999, Cook & Moore 2001, others –Youths exposed to lower MLDA drink more MLDA & mortality: panel evaluations –Lots of evidence on traffic fatalities (Dee 1999) –No consensus on other causes (suicide, injuries, homicides, etc.)

Limitations of MLDA Literature Exposure to a lower MLDA is not random –Reflects policy preferences, unobserved sentiment toward drinking, etc. MLDA effects on drinking typically small (e.g percent) Not all studies find effects (e.g. Kaestner 2000)

Our Contributions We have a transparent and robust research design much less vulnerable to OVB Most comprehensive examination of mortality Much more precise estimates (more data & refined age variable) We combine our consumption and mortality estimates to obtain the implied IV estimate

Research Design Focus on discrete change in access to alcohol at age 21 due to MLDA law Regression Discontinuity Design –Parametric: Model age profile with polynomial –Nonparametric: Local linear regression Evaluate research design –Check fit of models graphically –Check continuity of potential confounders

Regression Discontinuity Design Parametric –Polynomial in age fully interacted with a dummy for over age 21 (Ov21) Local Linear Regression –Follow Fan & Gijbels (1996) and estimate the rule of thumb bandwidth –Triangular Kernel

Data: Alcohol Consumption National Health Interview Survey (Sample Adult Supplement) –16,107 Adults Years of Age –Date of birth and date of interview –Questions about lifetime drinking, past year drinking participation, heavy drinking

Summary of Alcohol Findings There is an immediate persistent increase in alcohol consumption at age 21 Only modest evidence of an increase in first time use of alcohol More people are drinking but drinking intensity does not appear to have gone up much

Data: Mortality Vital Statistics Mortality –Exact date of birth and date of death –Census of Deaths in the United States –Considerable Detail on Cause of Death –We include dummies for large “birthday effects”

Summary of Mortality Findings Large, persistent increase in mortality Increase due largely to MVA but also evidence of an increase in suicides Implied IV: 10 percent increase in drinking days increases mortality by 4.3 percent

Conclusions Minimum Legal Drinking Age (MLDA) laws substantially reduce drinking and mortality The age profiles of consumption suggest it is not people’s first experience with drinking Main route is exposure (e.g. drinking days) Implied elasticities suggest a substantial amount of mortality among youths is due to drinking

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