Neighborhood – Cohen & Ludwig (2003)

Study Reference:

Cohen, J., & Ludwig, J. (2003). Policing crime guns. In J. Ludwig & P. J. Cook (eds.), Evaluating gun policy: Effects on crime and violence, (pp. 217–239). Washington, DC: Brookings Institution Press.

Location in the Matrix; Methodological Rigor; Outcome:

Neighborhoods; General; Proactive; Moderately Rigorous; Effective

What police practice or strategy was examined?

This study examined Pittsburgh’s firearm suppression patrol program implemented in 1998, which assigned more police resources to selected high-crime areas. The Pittsburgh Police Department assigned an additional patrol team, consisting of four officers and a sergeant traveling in three vehicles, to each of the city’s two highest-crime zones. The teams worked four-hour shifts from 8 p.m. to midnight twice weekly for fourteen weeks from July 19 to October 24, 1998. These patrols focused on the high-crime evenings of Wednesday through Saturday nights. The aim of these patrols was to solicit information and investigate suspicious activity associated with illegal carrying and use of guns through police contact such as traffic stops, pedestrian stops, and talks and searches.

How was the intervention evaluated?

The authors evaluated the intervention with a quasi-experimental design that compared the average number of gunshot injuries and shots fired calls in the two treatment zones and the city’s other four comparison zones during the 6 weeks before the intervention and the 14 weeks of the intervention. The authors further compared the differences in gun crime between the days of week when the intervention occurred (Wed. to Sat.) and the days when it did not occur (Sun. to Tue.) both within and between the groups of zones. 911 emergency call data and injury surveillance system data developed by the local Health Department were used to measure gunshot incidents and gunshot injuries, respectively.

What were the key findings?

The authors found suggestive evidence that targeted patrols focused on illegal gun carrying may reduce gun crime. Relative to the comparison zones, the program zones experienced a 34-percent decrease in shots fired calls and a 71-percent decrease in hospital-treated assault gunshot injuries during the program days. The actual number of arrests and guns confiscated as a result of the patrols, however, were modest.

What were the implications for law enforcement?

The authors suggest that using targeted patrols against illegal guns carrying is highly likely to be effective in reducing gun crime. It was unclear whether the program’s effects were due to targeting illegal gun carrying or simply adding more resources to routine patrol in these areas. However, the authors argued that targeting crime that involves firearms seems to enhance the cost effectiveness of the additional police resources, as firearm crimes are highly costly violent crimes.

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