Evidence-Based Policing Matrix
Micro Places – La Vigne et al. (2011) Chicago
La Vigne, N. G., Lowry, S.S., Markman, J. A., & Dwyer, A. M. (2011). Evaluating the use of public surveillance cameras for crime control and prevention. Chicago case study. Washington, DC: Urban Institute.
Location in the Matrix; Methodological Rigor; Outcome:
Micro places, General, Proactive; Rigorous; Mixed findings
What police practice or strategy was examined?
In Chicago, police operated 2,000 of the city’s 8,000 public surveillance cameras. Termed “PODs” for portable observation devices, the cameras were highly visible and were typically accompanied by both signage and blue flashing lights. Because the envisioned purpose of the system was to deter crime and aid in the arrest of perpetrators committing crimes in progress, cameras were placed in hot spots throughout the city. All sworn officers had the ability to monitor cameras from their desktop computers; however the extent of monitoring varied by police district.
How was the intervention evaluated?
The study collected data on the ways the cameras were employed in two areas and analyzed quarterly crime data for these areas from 2002 and 2003, with the intervention occurring in the third quarter of 2003. The researchers also examined crime trends in similar comparison areas (matched on historical crime volume, geographic location, land use, and demographics of the area) that did not receive cameras. Crimes examined include aggravated assault, arson, burglary, drug offenses, larceny, murder, motor vehicle theft, problem persons, prostitution, robbery, simple assault, sexual assault, vandalism, and weapons offenses. The net costs and benefits of camera implementation and use were analyzed as well.
What were the key findings?
Two areas with high concentrations of cameras were employed for the impact analysis. In one neighborhood, there was a significant decrease in average monthly total crime counts following camera installation, and the average monthly crime counts for drug-related and robbery offenses were reduced by nearly one-third. In the other area, only prostitution and robbery significantly changed, with prostitution increasing and robbery decreasing. The more successful area had a much higher concentration of cameras (approximately 53 per square mile) compared to the second neighborhood, which had approximately 36 cameras per square mile. A cost-benefit analysis found that for every dollar spent on cameras in both areas, the crimes prevented in the one successful area alone yielded a societal savings of over $4.00, providing compelling support for the implementation and use of public surveillance cameras by Chicago police.
What were the implications for law enforcement?
Police use of public surveillance cameras can be an effective and cost-beneficial crime prevention strategy, particularly when camera density is sufficiently high and the cameras are actively monitored and well-integrated into policing operations.
Where can I find more information about this intervention, similar types of intervention, or related studies?