Research

This paper estimates the impacts of doctor crackdowns on the quantity demanded of prescription opioids, across-market substitution, and across-product substitution. Exploiting plausibly exogenous variation in the timing and location of administrative actions, I find that cracking down on a single doctor decreases county-level opioid dispensing by 10%. This decline persists across space and grows over time. Additionally, significant heroin substitution occurs, yet overall overdose mortality decreases. These results highlight a critical tradeoff policymakers should consider with targeted crackdowns: reductions in the flow of new users must be balanced against the harm that arises when existing users substitute to more dangerous drugs.

In recent years, illicitly manufactured opioids—primarily heroin and fentanyl—have overtaken prescription opioids as the leading cause of overdose deaths in the United States. We provide the first causal evidence that geographically concentrated heroin purity shocks and supply-side adulteration of heroin with fentanyl played a central role in driving this transition. Using a difference-in-differences design that exploits the fact that white powder heroin markets—but not black tar heroin markets—were exposed to supply chain shifts beginning in 2012 that increased both the variability of heroin purity and the prevalence of fentanyl adulteration, we find that exposure to these shocks increased all-cause overdose death rates by approximately 50% and account for roughly half of the rise in illicit opioid deaths through 2019. These effects cannot be explained by previously studied policy efforts aimed at restricting prescription opioids. Our findings also help reconcile unexplained patterns in the opioid epidemic, including the sharp geographic shift in overdose deaths toward eastern states and rising mortality among populations less exposed to prescription opioids.

From 2005 to 2019, forty US states increased the dollar value threshold delineating misdemeanor and felony theft, reducing the expected punishment for a subset of property crimes. Using an event study framework, we observe significant and growing increases in theft after a state reform is passed. We then show that reduced sanctions for theft have broader effects in the market for illegal activity. Consistent with a mechanism of substitution across income-generating crimes, we find decreases in both drug distribution crimes and the probability that a released offender previously convicted of drug distribution is reincarcerated for a new drug conviction.

We provide novel evidence on the social spillovers of homeownership by exploiting the recent rise of institutional investors purchasing single-family homes and converting them to permanent rentals. Using a granular difference-in-differences design based on proximity to a single investor-purchased property, we find that neighboring property values decline by 1% relative to those slightly farther away. This decline grows over time yet decays across space, and these same properties experience increases in crime and decreases in property maintenance and voter registration. Heterogeneity analysis suggests that the observed externalities are primarily driven by changes in ownership rather than tenant behavior.

We still know very little about the incentives of police. Using geocoded crime data and a novel source of within-city variation in punishment severity, I am able to shed light on enforcement behavior. I find that in parts of a city where drug sale penalties were weakened, there is a 13% decrease in all drug arrests. There is no displacement of non-drug offenses. If offenders were significantly deterred by harsher penalties, as the law intended and Becker’s (1968) model predicts, drug arrests should have increased in areas with weaker penalties. My results are therefore consistent with police treating enforcement effort and punishment severity as complements. I also find that city-wide crime and drug use do not increase after the reform. This paper thus calls into question the "War on Drugs" view of punishment and suggests that certain types of enforcement can be reduced without incurring large public safety costs.