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Neighborhood – McGarrell et al. (2001)

Study Reference:

McGarrell, E. F., Chermak, S., Weiss, A., & Wilson, J. (2001). Reducing firearms violence through directed police patrol. Criminology and Public Policy, 1, 119-148.

Location in the Matrix; Methodological Rigor; Outcome:

Neighborhood, General, Proactive; Moderately Rigorous; Mixed findings

What police practice or strategy was examined?

This study examines the use of two types of directed police patrol approaches to reduce firearms violence in Indianapolis, implemented in two different target beats. One intervention included the use of increased traffic enforcement to reduce crime, where officers focused on maximizing the number of vehicle stops for traffic violations, such as speeding, rolling through stop signs, expired license tags, inoperable tail lights, and the like. The second involved a more focused targeting of suspicious persons for both traffic and pedestrian stops. The idea was to target resources toward individuals suspected to be involved in illegal behavior while seeking to maximize seizures of illegal weapons and drugs through the more thorough investigation. Additionally, the supervisor of this second strategy decided to have officers pair up with probation officers and conduct home visits.

How was the intervention evaluated?

Two treatment areas were chosen for the project based on very high rates of violent crime for the area size of the beats, and a nonequivalent control area was also selected for comparison. The authors also compared the targeted areas with city-wide changes in crime. In one analysis, a 90-day intervention period for the treatment and control areas were compared with the same 90-day period of the previous year to control for seasonal effects. In a second analysis, the researchers developed time-series models to test whether changes observed during the intervention period were significantly different from pre- and post-intervention trends in violent crime, comparing the targeted and comparison areas. Firearm-crime related outcomes examined included homicide, aggravated assault with a gun, armed robbery, as well as a total gun crimes measure.

What were the key findings?

The increased traffic enforcement strategy did not appear to have a significant effect on violence. However, the more focused pedestrian and traffic stop strategy in which the police utilize directed patrol to focus on suspicious activities and locations, reduced aggravated assaults with a gun and armed robbery by 40%. These were statistically significant declines compared with both the comparison beats and the citywide trend.

What were the implications for law enforcement?

This research suggests that targeted offender/specific deterrence approach may be a more effective mechanism for reducing firearms-related violence than a general blanketed traffic enforcement approach. This finding is consistent with prior research that suggests that crackdowns that focus on specific types of crime in specific locations have the most effect on crime. The authors caution, however, that in light of the impact of traffic and pedestrian stops on racial and ethnic minorities and communities, that such strategies should be implemented with respect and dignity, and in consultation with community members and leaders in targeted communities.

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