"Does Ridesharing Affect External-Cause Mortality? Evidence from U.S. Vital Statistics Data" (with Keith Teltser and Conor Lennon)Â
Journal of Public Economics, Vol. 263: 105813 (2026)
Media Highlights: National Affairs
Existing research suggests ridesharing affects transportation access, substance use, and exposure to crime. Ridesharing may therefore also have meaningful effects on mortality related to these underlying factors. To address this issue, we use restricted-access data from the National Vital Statistics System to study how ridesharing affects mortality from external causes. Our identification strategy relies on spatial and temporal variation in UberX entry across U.S. counties. Among those aged 18 to 45, we find that UberX entry into an area is associated with 2.01 additional deaths per quarter per 100,000 population (roughly a 10% increase). We find that these deaths are primarily related to alcohol and drug use. We support a causal interpretation of our findings by presenting event studies, placebo analyses, sensitivity and heterogeneity analyses, and a variety of robustness checks, including difference-in-differences estimators that are robust to heterogeneous treatment effects. Our work contributes to the literature by addressing both the benefits and costs of ridesharing, and by informing stakeholders who are interested in the cumulative impact of ridesharing on public health and well-being.
"The Returns to Regulatory Redundancy: Evidence from Tobacco 21" (with James Flynn and Michael Pesko) Under Review
We consider the impact of state laws that prohibit conduct already barred under federal law. In particular, we examine the effectiveness of state minimum legal sales laws for tobacco, or tobacco 21 laws, implemented after the federal T21 law in December 2019. Using difference-in-differences modeling that exploits the staggered implementation of tobacco 21 legislation (T21) in 28 states after 2019, we find that these state T21 laws consistently have little to no effect on smoking and vaping among adults ages 18 to 20, nor for high school youth. Our findings indicate that state T21 laws offer little marginal benefit under a unified federal T21 regime. We discuss voluntary compliance as a likely explanation for these findings.
"Pharmaceutical Drug Regulation and Mortality: Evidence from E-cigarettes" (with Michael Pesko) Under Review
Media Highlights: Marginal Revolution, Vox, National Affairs, Cato Institute
This study evaluates drug regulation in the United States by examining the effects of the unexpected judicial exemption of e--cigarettes from drug regulation, compared to nicotine replacement therapy, which remained regulated as a drug. We find that this exemption led to significant increases in innovation, as evidenced by a rise in patent applications. Using variation in smoking rates across demographic groups prior to e-cigarette introduction, we estimate that from 2011 to 2019, e-cigarettes saved 677,000 life-years-approximately one-third of the estimated benefit of early HIV/AIDS drugs by year 2000-and increased social surplus by $8 billion annually. We show that reduced smoking is a key mechanism behind this mortality reduction, with statistically significant declines in mortality lagging smoking reductions by approximately four years.