Micro Places – Piza (2018)

Study Reference:

Piza, E. L. (2018). The crime prevention effect of CCTV in public places: A propensity score analysis. Journal of Crime and Justice, 41(1), 14-30.

Location in the Matrix; Methodological Rigor; Outcome:

Micro places; General; Proactive; Rigorous; Mixed effects

What police practice or strategy was examined?

This study examined the effect of a CCTV system in Newark, NJ on three crime categories: auto theft, theft from a vehicle, and violent crime. Between 2007 and 2010, the city installed cameras in five different phases. Two CCTV operators working under a police sergeant monitored live footage from the cameras during every shift.

How was the intervention evaluated?

The study used propensity score matching to match target areas to statistically similar control areas. 141 of the 146 cameras in Newark were used in the analysis (the remaining five were out of service). Some cameras had overlapping views and were combined into single units for the analysis. This resulted in 117 final street intersection “viewsheds” (i.e., small locations within the view of one or more cameras) installed over four dates – March 15, 2008 (44), July 31, 2008 (50), December 10, 2009 (13), and April 23, 2010 (10). For the control group, street intersections without CCTV cameras were identified and matched to the target places based on crime and arrest incidents one year before camera installation, police precinct, and socio-demographics. The CCTV effect was measured using crime data on auto thefts, thefts from vehicles, and an aggregate violent crime measure that included incidents of murder, non-fatal shootings, and robberies.

What were the key findings?

Modest evidence was found to support CCTV as a deterrent to auto thefts. Specifically, a statistically significant 21% reduction in auto thefts was observed when comparing all treatment viewsheds to control viewsheds. However, the authors also conducted a micro-level analysis which compared each individual treatment viewshed to its matched control viewshed. The average effect across these comparisons was not statistically significant for any analyzed crime type. Additionally, no significant reductions in thefts from vehicles or violent crime were observed across any reported analyses.

What were the implications for law enforcement?

The authors suggest that while CCTV can be a moderately effective tool for reducing auto thefts, police should implement other evidence-based strategies alongside CCTV, especially if other crime types are of concern. A large camera network might deter auto theft more effectively given that cameras can follow a stolen vehicle around the city.

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