Research
Publications
Police Violence and Civic Engagement (with Desmond Ang)
American Political Science Review, 2023.
Roughly a thousand people are killed by American law enforcement officers each year, accounting for more than 5% of all homicides. We estimate the causal impact of these events on civic engagement. Exploiting hyperlocal variation in how close residents live to a killing, we find that exposure to police violence leads to significant increases in registrations and votes. These effects are driven entirely by Black and Hispanic citizens and are largest for killings of unarmed individuals. We find corresponding increases in support for criminal justice reforms, suggesting that police violence may cause voters to politically mobilize against perceived injustice.
Working Papers
Do Pedestrian Stops Deter Crime? Evidence from Reforming “Stop and Frisk” (with Jeffrey Fagan)
Over 3.5 million pedestrians are stopped by police in the United States every year. We explore the impact of investigative pedestrian stops on criminal activity by leveraging a lawsuit that abruptly reduced stop rates in New York City without altering patrol officer presence. We implement a difference-in-differences strategy that compares crime trends following the reform between neighborhoods with similar historical crime rates but differing historical stop rates. We find neighborhoods that experienced twice the reduction in stops did not exhibit differential increases in felonies and violent misdemeanors, major felonies, shootings, killings, or a cost-weighted crime measure over the five years following the reform. Our estimates are precise, ruling out a 1.5% increase in felonies and violent misdemeanors. In contrast, police surges that increased both officer presence and stops were found to reduce major felony crime, highlighting the importance of officer presence but not pedestrian stops for crime deterrence.
[Formerly, Stopped by the Police: The Effect of Reforming “Stop and Frisk” on Crime and High School Engagement (with Jeffrey Fagan) ]
Racial Bias in Police Stopping Decisions (with Jeffrey Fagan)
This paper explores whether racial disparities in pedestrian stops arise due to racial differences in criminal pedestrian behavior or racial discrimination by the police. Motivated by a model of officer stopping decisions, we leverage a court-initiated reform that sharply reduced stop rates across New York City, allowing us to estimate outcomes of marginal stops – stops that would have occurred before but not after the reform – separately for each racial group. Using a local average treatment effect framework, we instrument for an officer’s stopping propensity with the timing of the reform, circumventing common pitfalls of outcomes tests, such as omitted variables bias and infra-marginality bias. Comparing marginal stop outcomes in the first year of the reform reveals that Black and Hispanic pedestrians were over-stopped: marginal white stops were 45% more likely to detect criminal behavior than marginal Black and Hispanic stops (p = 0.001). By tracing out race-specific marginal hit rate curves, we estimate that over 70% of Black and Hispanic stops were less productive than the final white stop– implying that racial gaps in stop rates before the reform were inefficient. Heterogeneity analyses by pedestrian demographics, neighborhood crime rates, and officer tenure suggest that stereotypical prediction errors played a central role in generating racial bias, although we cannot rule out the presence of racial animus.
Research in Progress
Policing Minor Offenses and the Early-life Trajectory of Urban Men: Evidence from Court, School, and Tax Records (with Benjamin Goldman)
Academic and Athletic Mentorship: A Randomized Trial of Multi-Faceted Mentorship (with Noam Angrist)
Can Emergency Financial Assistance Prevent Financial Distress? Randomized Evidence from Funeral Assistance in Chicago (with Mary Kate Batistich) [AEA Registry, PAP]
Mentoring Across Lines of Difference: Randomized Evidence on Comprehensive Mentorship for Students At Risk of Dropping Out of High School (with Bill Evans and Sarah Kroeger) [AEA Registry]
Supporting Pathways out of Poverty: Randomized Evaluation of Mobility Mentoring (with Larry Katz and Liz Engle) [AEA Registry]
Seeing is Believing? A Cognitive View of Program Take-up (with Olga Stoddard and Patrick Turner) [AEA Registry]
Empowerment as Engagement: Randomized Evidence on School-based Girls Empowerment Curriculum (with Mary Kate Batistich) [AEA Registry]
Does Social Emotional Learning Complement Academic Learning? Randomized Evidence from the "Boys and Girls Club" (with Mike Kofoed) [AEA Registry]
Leveling the Playing Field: Athletics and the Academic Achievement of Disadvantaged Youth (with Caroline Chin, Jamie Emery, and Clare Suter)
Elevating Families: Randomized Evidence on Goal-oriented Case Management for Low-income Parents and their Children (with Tyler Giles) [AEA Registry]
Fostering Independence: Can Incentivized Case Management and Savings Accounts Improve Early-life Outcomes of Youth Aging out of Foster Care? (with Chris Mills)