Journal Articles (Refereed):

Chalfin, Aaron, Benjamin Hansen, Emily K. Weisburst, and Morgan C. Williams Jr. “Police Force Size and Civilian Race.” American Economic Review: Insights 4, No. 2 (2022): 139-58.

Abstract: We report novel empirical estimates of the race-specific effects of larger police forces in the United States. Each additional police officer abates approximately 0.1 homicides. In per capita terms, effects are twice as large for Black versus White victims. Larger police forces also make fewer arrests for serious crimes, with larger reductions for crimes with Black suspects, implying that police force growth does not increase racial disparities among the most serious charges. At the same time, larger police forces make more arrests for low-level “quality-of-life” offenses, with effects that imply a disproportionate impact for Black Americans.

O’Flaherty, Brendan, Rajiv Sethi, and Morgan Williams Jr. “The Nature, Detection, and Avoidance of Harmful Discrimination in Criminal Justice.” Journal of Policy Analysis and Management 43, No. 1 (2024): 289-320.

Abstract: We provide a selective survey of the literature on discrimination by criminal justice agents, and argue for a taxonomy of harms that differs from conventional approaches. Discrimination can be self-defeating if it reduces welfare among targets of discrimination while serving no legitimate purpose for the discriminating party. Even if a legitimate purpose is served, discrimination can be deliberative or demeaning, resulting in welfare losses that need to be accounted for. Deliberative and demeaning discrimination can also be self-defeating through general equilibrium effects on witness cooperation, clearance rates, and preemptive and retaliatory violence. We consider how harmful discrimination can be detected and avoided, as well as changes in our understanding of discrimination resulting from the proliferation of predictive algorithms.

Chalfin, Aaron, David Mitre-Becerril, and Morgan C. Williams, Jr.  “Does Proactive Policing Really Increase Major Crime?  A Replication Study of Sullivan & O’Keeffe (Nature Human Behavior, 2017).”  Forthcoming, Journal of Comments and Replications in Economics, 2024.

Abstract: In December 2014 and January 2015, police officers in New York City engaged in an organized slowdown of police work to protest the murder of two police officers who were targeted by a gunman while sitting in their patrol car.  An influential 2017 article in Nature Human Behaviour studies the effect of the NYPD’s work slowdown on major crimes and concludes that the slowdown led to a significant improvement in public safety.  Contrary to the remainder of the literature, the authors conclude that proactive policing can cause an increase in crime. We re-evaluate this claim and point out several fatal weaknesses in the authors’ analysis — which purports to be a difference-in-differences analysis but isn’t — that call this finding into question. In particular, we note that there was considerable variation in the intensity of the slowdown across NYC communities and that the communities which experienced a more pronounced reduction in police proactivity did not experience the largest reductions in major crime. The authors’ analysis constitutes a quintessential fallacy in statistical reasoning, a logical miscalculation in which inferences from aggregated data are mistakenly applied to a more granular phenomenon. We raise several additional and equally compelling concerns regarding the tests presented in the paper and conclude that there is little evidence that the slowdown led to short-term changes in major crimes in either direction.

Working Papers:

Gun Violence in Black and White: Evidence from Policy Reform in Missouri

Abstract: The extent to which gun control policies contribute to the significant racial disparities in U.S. gun violence remains largely unexplored in the empirical gun control literature.  On August 28, 2007 the Missouri General Assembly repealed an 86 year-old “permit-to-purchase” (PTP) law requiring that handgun purchasers possess a permit, and subsequently undergo a background check, for all sales.  Using generalized synthetic control methodology, this paper examines the impact of the 2007 Missouri PTP repeal on city-level gun violence and enforcement activity across racial groups.  Estimates suggest that the repeal led to exponential growth in statewide FBI handgun background checks among licensed dealers and a 24 percent increase in the fraction of suicides committed with a firearm (FSS) within the City of St. Louis and Jackson County.  Within St. Louis and Kansas City, the repeal led to a 19 percent increase in Black firearm homicide and a 22 percent decrease in Black non-gun homicide primarily driven by weapon substitution among Black youth.  The escalation in Black gun violence coincides with a 125 percent decrease in aggravated assault arrests and a 44 percent decrease in weapons arrests among Black suspects.  While this study largely finds no evidence of significant changes in White homicide victimization and enforcement activity, law enforcement officers themselves experience an additional 2.33 gun assaults per 100 officers.  The disproportionate shifts in gun violence, and declines in policing productivity, remain consistent with a preemption model in which strategic complementarities in violence contribute to disproportionate changes in homicide across racial groups as firearms become more readily available.

Body-Worn Cameras and Policing: Benefits and Costs (with Nathan Weil, Elizabeth A. Rasich, Jens Ludwig, Hye Chang, and Sophia Egrari)

Abstract: Body-worn cameras (BWCs) are an increasingly common tool for police oversight, accountability, and transparency, yet there remains uncertainty about their impacts on policing outcomes. This paper reviews what we know about the benefits of BWCs and how those benefits compare to the costs of this new technology. We make two contributions relative to existing research. First, we update prior meta-analyses of studies of the impacts of BWCs on policing outcomes to incorporate the most recent, and largest, studies carried out to date in this literature. This additional information provides additional support for the idea that cameras may affect a number of policing outcomes that are important from a social welfare perspective, particularly police use of force. Second, we carry out a benefit-cost analysis of BWCs, as financial barriers are often cited as a key impediment to adoption by police departments. Our baseline estimate for the benefit-cost ratio of BWCs is 4.95. Perhaps as much as one-quarter of the estimated benefits accrue to government budgets directly, which suggests the possibility that this technology could, from the narrow perspective of government budgets, even pay for itself.

The Effects of Compulsory Schooling on Health and Hospitalization over the Life-Cycle (with Markus Gehrsitz)

Abstract: Despite serving as one of the more celebrated relationships in health economics, evidence on the relationship between education and health remains quite mixed–with limited research devoted to how these effects evolve later in life. Leveraging a 1972 compulsory schooling reform within the United Kingdom, this paper examines the effects of education on health and health care utilization over the life cycle. Our regression discontinuity estimates suggest that the reform led to substantial reductions in hospitalization among men for lifestyle-related conditions–with these effects varying heterogeneously over the life cycle.

Work in Progress:

Health Insurance and Recidivism: Evidence from New York State Medicaid Policy (with Sherry Glied and Renata Howland)

Searching for a Second Chance: Evidence from Local New York State “Ban-the-Box” Laws

(with Jed Armstrong and Glenn C. Loury)