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)

Conditionally Accepted at American Economic Journal: Economic Policy.

We examine whether investigative pedestrian stops per se deter crime by exploiting a lawsuit that dramatically reduced stop rates in New York City while leaving police presence largely unchanged. Using a difference-in-differences approach, we compare crime trends across neighborhoods with similar historical crime rates but different stop rates. Neighborhoods experiencing twice the decline in stops showed no detectable differential increases in various serious crimes including felonies and shootings over five years post-reform, ruling out increases as small as 1.5%. However, police surges that increased both presence and stops reduced major felonies, suggesting officer presence rather than stop activity deters crime.

[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 Lily Morrell and Jeffrey Fagan)

Under Review.

Do racial disparities in pedestrian stops reflect differences in criminal behavior or bias in police decisions? Leveraging a court-ordered reform in New York City that reduced officer stopping behavior, we estimate the hit rate of stops deterred at the margin. We find evidence of racial bias: marginal stops of white pedestrians were 45% more likely to detect criminal activity than marginal stops of minority pedestrians (p=0.001). The gap is five times larger than conventional OLS comparisons, illustrating how inframarginality bias masks discrimination. Consistent with inaccurate statistical discrimination and learning, officers appear to overestimate risk for young minority men in high-crime areas and the racial gap shrinks with officer tenure.

Building Holistic Human Capital: Long-run Randomized Evidence on Athletic and Academic Mentorship (with Noam Angrist)

Under Review.

We evaluate the long-run effects of a mentorship program combining athletic coaching in swimming and rowing with academic tutoring for disadvantaged high school students. Program access was determined by lottery in oversubscribed semesters, enabling randomized evaluation. We track administrative outcomes for more than a decade after application, including high school achievement and graduation, post-secondary attainment, and leading labor market indicators from credit-bureau records. We find large and persistent effects: admission offers increased high school GPA by 0.48–0.58 standard deviations and graduation by 17–18 percentage points. Bachelor’s degree completion rose by 17–21 percentage points through greater persistence, not increased college entry. In early adulthood, labor market indicators also improved substantially: an aggregate credit index rose by 0.37–0.38 standard deviations, while a poor-financial-health index fell by 0.40–0.43 standard deviations. The program was unusually low-cost because it leveraged college-student volunteers and university facilities, placing it among the most cost-effective youth interventions. Mechanism analyses show persistent gains in both cognitive and non-cognitive skills, suggesting large and lasting returns to programs that build holistic human capital.

Research in Progress

The Long Shadow of Stop-and-Frisk: Policing and Economic Mobility in Urban America (with Benjamin Goldman)

Can Emergency Financial Assistance Prevent Financial Distress? Randomized Evidence from Funeral Assistance in Chicago (with Jackson Alexander and 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] 

Texas Reimagines Rehabilitation: Evidence from a Prosocial Prison Dorm on Recidivism, Reskilling, and Labor Market Outcomes (with Benjamin Feigenberg)

Paying for Peace: Can Cash Incentives and Wraparound Support Reduce Gun Violence Among Actively Gang-Involved Men? 

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]

Does Social Emotional Learning Complement Academic Learning? Randomized Evidence from the "Boys and Girls Club" (with Mike Kofoed)  [AEA Registry]

Empowerment as Engagement: Randomized Evidence on School-based Girls Empowerment Curriculum (with Mary Kate Batistich)  [AEA Registry]

Elevating Families: Randomized Evidence on Goal-oriented Case Management for Low-income Parents and their Children (with Tyler Giles) [AEA Registry]