Hot Spots, Patrolling Intensity, and Robberies: Lessons from a three-year program in Uruguay

We study the effects of increasing police presence on crime by exploiting the quasi-experimental nature of a large-scale hot spots intervention in a Latin American country that had experienced a significant increase in crime over the last 30 years. We match geocoded data on crime and GPS data that signals the presence of police to 200x200 meters cells covering Montevideo, Uruguay. Employing a difference-in-differences (DiD) approach, our results suggest that the program effectively increased police presence in the designated areas and reduced crime. We found an overall elasticity of 0.47 - a 10% increase in police presence is associated with a decrease of 4.7% in robberies. This three-year intervention allows us to investigate heterogeneous effects by year of intervention and contexts. The program presented greater effects during the first year of the intervention; during 2017, a period associated with significant legal changes in the country's criminal policy, the program did not affect crime. In 2018, we observed positive results in police presence and crime reduction but at a reduced level. We associated this reduction in outcomes with program fatigue which could impact the sustainability of this type of intervention. This study may help policymakers identify the conditions under which hot spots policing programs work and the degree to which they are replicable and scalable.