Micro Places – Munyo & Rossi (2020)

Study Reference:

Munyo, I., & Rossi, M. A. (2020). Police‐monitored cameras and crime. The Scandinavian Journal of Economics, 122(3), 1027–1044.

Location in the Matrix; Methodological Rigor; Outcome:

Micro places; General; Proactive; Moderately Rigorous; Effective

What police practice or strategy was examined?

This study evaluated the effects of police monitoring on crime in Montevideo, Uruguay. Police monitoring consisted of the implementation of surveillance cameras, which were continuously monitored by police officers in a monitoring center, at 277 street segments. Officers monitoring the surveillance cameras would contact mobile patrol officers in the area after a crime was observed. Mobile patrol officers had an average response time of five minutes. Officers were instructed to arrest the offenders during their response. In addition to this, police were tasked with increased patrolling in the targeted areas.

How was the intervention evaluated?

A difference-in-differences approach was used to evaluate the intervention between January 2012 and December 2014 using monthly data. The authors compared treated street segments based on the timing of their camera installation and compared treated streets segments to all other street segments within the city. They also compared treated jurisdictions within Montevideo to other jurisdictions outside Montevideo that were not treated. Total crime, indoor crime, and outdoor crime were all evaluated.

What were the key findings?

The street segment analyses suggested the cameras reduced crime from 19% to 30% depending on the comparisons used. These effects were due to reductions in outdoor crimes (like robbery and theft) which declined from 22% to 30%. There was no effect of surveillance cameras on indoor crimes (assault and domestic violence). Treated areas within Montevideo had a 20% reduction in outdoor crime relative to other jurisdictions. Untreated areas within Montevideo also had an 18% decline in outdoor crimes relative to untreated jurisdictions (the authors interpreted this as a possible diffusion of crime control benefits from treated to untreated areas of Montevideo).

What were the implications for law enforcement?

The authors suggest that police-monitored surveillance cameras and increased police presence can significantly reduce street crimes. The authors emphasize the need to interpret these results as a joint effort between the two interventions: surveillance cameras and increased police patrolling.

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