Research Projects
Place-based interventions in a high violence environment (with Michael Weintraub and Isabela Salgado)
Street crime is highly concentrated at a small number of micro-places, and hot spot policing has been shown to reduce crime with limited displacement. Almost all of this evidence, however, comes from cities in the Global North, where police can deploy anywhere in the city. It is unclear whether place-based strategies work in highly violent cities where the state has only partial territorial control. This study evaluates the Força Municipal (FM-Rio), an armed, highly selected and intensively trained municipal police unit created in Rio de Janeiro in 2025. FM-Rio patrols only hot spot street segments, at peak crime hours, with a single mandate: preventing robberies and thefts in public spaces. Although Rio is one of the world’s most violent cities, half of its street robberies occur on 1.4% of street segments. Deployment is paired with situational interventions coordinated through CompStat Rio, including improvements to lighting, vegetation, abandoned infrastructure and public disorder. We exploit the staggered rollout of FM-Rio across 22 clusters containing 535 hot spot segments, beginning in March 2026. We use a heterogeneity-robust difference-in-differences design (Callaway and Sant’Anna, 2021) with not-yet-treated clusters as the comparison group. We estimate effects on street robberies and thefts across all hours and within scheduled patrol windows, and effects on police activity outputs such as stops, detentions and seizures. We also estimate spatial spillovers to nearby hot spot and non-hot spot segments within 500 meters. Finally, we run an exploratory analysis of whether the situational interventions are associated with lower crime before patrols arrive.
Registered Pre-Analysis Plan
Shedding Light on Criminal Territorial Control (with Vinicius Peçanha, Ana Paula Pellegrino, Ramón Chaves, Mathias Lusquiños)
Organized criminal groups (OCGs) have controlled large portions of Rio de Janeiro’s territory for decades. Despite the centrality of this phenomenon to the city’s security landscape, systematic data on where these groups operate and how they affect civilian life remain scarce. To address this gap, we partnered with Light–Rio de Janeiro’s electricity company–to construct a dataset that maps territorial control exerted by criminal groups and evaluates their influence on private service provision. By leveraging the company’s extensive operational capacity–its workforce is deployed daily across virtually all Rio’s metropolitan area—we aim to generate a detailed, high-frequency dataset on territorial control by criminal organizations.
Athletes for Peace: Exploring the Role of Sports and Emotional Skills in Preventing Youth Violence in Brazil’s Favelas (with Julia Guerra and Lelys Dinarte-Diaz)
Militarized policing strategies to combat high homicide and violent crime rates are common across the developing world. While empirical evidence on the effectiveness of militarized policing in Latin America is weak—the only randomized militarized policing intervention, in Cali, Colombia, showed no crime reduction effects (Blair and Weintraub 2023a) – we still understand little about how militarized patrols are deployed throughout the region, whether they are effective, and what their secondary consequences might be. In cooperation with the Ceará government, we will conduct two quasi-experimental impact evaluations of RAIO patrols. The first exploits the rollout of RAIO bases across Ceará’s 184 municipalities. The second uses high-frequency GPS data from RAIO patrols within Fortaleza and leverages plausibly exogenous variation in exposure to those patrols to assess whether RAIO patrols decrease crime. A citizen survey of nearly 3,000 respondents – including embedded s the military, and the police. This project aims to assess the impact of Athletes for Peace program, a sports-based and social-emotional learning (SEL) intervention targeting youth violence and crime reduction in Maré, an area of Brazil marked by the presence of armed criminal groups. In partnership with Fight for Peace, the pilot will test school-based recruitment strategies and assess the feasibility of survey instruments and new data tools to measure outcomes such as emotional regulation, mental health, and peer dynamics in a challenging security context. Additionally, the study will evaluate the availability and quality of administrative records for tracking long-term impacts and develop a monitoring platform to collect data on costs and implementation fidelity. Insights from this pilot will shape the full randomized evaluation in 2026, providing critical evidence for NGOs and policymakers in Brazil on effective strategies to address youth violence and crime in the short and long-run.
Financial Support: JPAL.
This project evaluates the impact of Força Municipal (FM-Rio), an armed municipal police unit created in Rio de Janeiro in 2025 and deployed exclusively to hotspot street segments with the mandate to prevent robberies and thefts in public spaces. Despite its reputation as one of the world’s most violent cities, street robbery in Rio de Janeiro is highly concentrated: 50% of all street robberies recorded between 2023 and 2024 occurred in 1.4% of street segments, a degree of concentration comparable to that documented in Seattle, Boston, and Tel Aviv (Weisburd, 2015). This pattern motivated a place-based intervention and makes Rio de Janeiro a theoretically important test case for the generalizability of hot spot policing to high-violence urban environments. We evaluate the program using a difference-in-differences design that exploits the staggered rollout of FM-Rio across 22 hot spot clusters, comparing treated street segments to comparable untreated hot spot segments over a two-year pre-treatment period and a twelve-month post-deployment window. Beyond the direct effect on crime, we estimate spatial spillover effects distinguishing displacement toward nearby high-crime locations from broader diffusion of benefits.