The Deterrent Effect of Public Surveillance Cameras on Crime

We investigate if there is any effect on crime following the installation of public surveillance cameras. To do so, we benefit from a quasi-experiment that took place in Medellin, Colombia with the installation of 587 cameras between 2013 and 2015. We highlight three main findings. First, there is a statistically significant decline in total crime after the installation of the cameras. On average, total crime reports are 23.5% lower within the coverage zone following the installation of a camera relative to the average baseline level of crime reports. Second, we also find a statistically significant decline in arrests. The magnitude of this effect is 31.5% relative to the average baseline level of arrests. Along with the facts that the monitoring capacity of the system of public surveillance cameras is low and decreased during the installation period, and the two year installation period is unlikely to allow for the public surveillance cameras to be used by the criminal justice system for aggravated sentences, these results suggest that the effect of the surveillance cameras on reported crime are driven by a deterrent effect on potential offenders. Third, we do not find any crime spillover effects after the installation of the cameras nor we see any diffusion of benefits to surrounding places