Micro Places – Gómez et al. (2021)

Study Reference:

Gómez, S., Mejía, D., & Tobón, S. (2021). The deterrent effect of surveillance cameras on crime. Journal of Policy Analysis and Management, 40(2), 553-571.

Location in the Matrix; Methodological Rigor; Outcome:

Micro places; General; Proactive; Moderately Rigorous; Effective

What police practice or strategy was examined?

This study examined the impacts of public surveillance cameras on crime in Medellín, Colombia. In 2013, the Information System for Citizen Security Office of the Department of Security of Medellín identified 587 crime hot spots for camera installation based on reported crime data, previously installed cameras, and the availability of new ones. The locations of the hot spots were validated by field teams during on-site visits. Between May 2013 and April 2015, 448 out of 587 cameras were installed, and the remaining 139 cameras were set up by 2018. Thirty-six operators monitored the cameras, working three eight-hour shifts of twelve people each. Four were civilians hired by the Department of Security, while the remaining eight were police personnel.

How was the intervention evaluated?

Researchers constructed a panel data set consisting of 22,571 grids of 70´70 meters each, all within a 500-meter distance of the 587 pre-selected sites for camera installation. These grids were classified based on their proximity to operational surveillance cameras into three categories: those within 120 meters for direct surveillance, those between 120 and 300 meters for spatial spillovers, and those beyond 300 meters as control groups. Before the installation of the cameras, there were no differences in crime patterns between treatment and control areas, and spillover and control areas. Researchers compared the monthly crime and arrest reports within these areas from January 2012 through July 2015.

What were the key findings?

The study found that areas under direct surveillance by cameras experienced a significant reduction in crime: there was a 17% decrease in property crimes and a 26% decrease in violent crimes. There was no evidence of crime displacement for either type of crime. As for arrests, the study observed a 5% increase in arrests in spillover areas. Further analysis showed that there was an 11% reduction in arrests within 60 meters of camera locations.

What were the implications for law enforcement?

This study provides further evidence that public surveillance cameras are effective in reducing crime in urban areas of Latin America. The study found that such cameras do not lead to the displacement of criminal activity to nearby areas. Researchers suggest that investing in surveillance cameras is cost-effective given the social costs incurred by criminal activities outweigh the expenses related to the installation and maintenance of cameras.

Where can I find more information about this intervention, similar types of intervention, or related studies?