Piza, E. and O’Hara, B. (2014)
Justice Quarterly, 31(4): 693-718
- The Newark, NJ Police Department deployed a team of foot patrol officers in a 0.25 sq. mi. target area from 6pm-2am on a nightly basis
- The evaluation measured the effect of the foot patrol intervention as compared to 2 separate control areas over a 1-year period
- Total street violence as well as the disaggregate categories of aggravated assault and non-fatal shootings significantly decreased absent any displacement
- Robbery suffered from substantial levels of both spatial and temporal displacement
- Police should design large-scale foot patrol interventions in a manner that doesn’t allow robbers to easily gauge the scope of the intervention
In the summer of 2008 the Newark, NJ Police Department (NPD) commenced Operation Impact, a saturation foot patrol intervention modeled after an NYPD strategy of the same name. On a nightly basis, 12 police officers under the supervision of three supervisors patrolled a quarter-square-mile area of the city. Operation Impact patrols occurred from 6pm to 2am each night to coincide with the times which violence was highest in the target area. Foot-patrols were deployed as a deterrence mechanism to communicate increased risk of apprehension to potential offenders. NPD officials further expected the proactive activity of foot-patrol officers to disrupt street-level disorder and narcotics activity that may present opportunities for violence.
To measure the effect of the intervention, crime incidents were measured within four areas for the one year pre- and post-intervention periods: the target area, a catchment zone (meant to measure spatial displacement), and two control areas: the surrounding police precinct and a prospective target area, “Zone B,” identified during the analysis phase. Separate controls were incorporated to provide added perspective to any observed crime changes in the target area. Operation Impact’s intensive foot patrol approach is compared with tactics specific to the two control areas: intermittent, place-based enforcement in Zone B and “standard” responses to crime in the precinct. Any reductions would need to outperform both control areas to unequivocally validate the strategy.
Overall violence reduced by about 42% in the target area as compared to the precinct control area, with shootings and non-domestic aggravated assaults reducing over 60%. Operation Impact sustained its positive effect when compared to Zone B, albeit to a lesser extent. Compared to Zone B, overall violence and aggravated assault reduced by 30% and 61%, respectively, in the target area. While the crime reduction reflects favorably upon Operation Impact, the displacement an lysis highlights certain challenges pertaining to robbery. During the non-operational period, robbery increased in the target area from 15 to 26 incidents (73%), which was more than double the increase observed in Zone B during the same time period. No other crime types increased in the target area during the non-operational period.
The spatial displacement analysis found that shootings experienced a modest diffusion of benefits effect, with significant decreases observed in the catchment area. Overall violence experienced an overall level of spatial displacement that was less than the reduction achieved within the target area. However, spatial displacement occurring during the non-operational period was larger than the target area reduction. A review of the raw counts shows robbery to be predominately responsible for this spatial displacement. Robbery increased 96% (from 25 to 49) in the catchment area. During the non-operational period robbery in the catchment area more than doubled (from 13 to 30) with an increase of 58% (from 12 to 19) observed in the catchment area during operational hours.
On a whole, this study offers support for foot patrol as a violence reduction tool, with Operation Impact reducing overall incidents of violence as well as the disaggregate categories of shootings and aggravated assault. However, while the place-based policing literature demonstrates displacement is far from inevitable, the robbery findings serve as a reminder that displacement can be a threat to crime prevention efforts. In light of these observations, additional effort may be necessary in order to avoid displacement if crime patterns include substantial levels of robbery.