Spatial Displacement and Diffusion of Benefits Among Geographically Focused Policing Initiatives

• NCJ Number: 235760
• Author(s): Kate Bowers; Shane Johnson; Rob . T. Guerette; Lucia Summers; Suzanne Poynton
• Date Published: April 2011
• Length: 147 pages
• Sponsoring Agency: National Policing Improvement Agency (NPIA); Center for Evidence-Based Crime Policy
• Corporate Author: Campbell Collaboration
• Sale Source: Campbell Collaboration
• Publication Format: Document; Document (Online)
• Publication Type: Report (Study/Research)
• Language: English
• Country: Norway

Annotation

This report synthesizes the evidence regarding the degree to which geographically focused police interventions are linked to the displacement of crimes to untargeted areas well as the diffusion of the intervention's impact to crime reductions in untargeted areas.

Abstract

The study concludes that the studies reviewed show that police interventions in targeted geographic areas do not inevitably result in crime displacement to untargeted areas. The studies found that the more likely impact of such interventions is to diffuse crime-control benefits to untargeted geographic areas. The main findings of this meta-analysis indicate that on average geographically focused policing initiatives for which data were available were linked with significant reductions in crime and disorder in the targeted area and that any associated increases in crime in nearby areas were insignificant; diffusion of crime-control benefits was the more likely result. For all of the 44 eligible studies included in this review, this study produced a narrative review and a summary of the author's findings. For the 16 studies that contained pre-measures and post-measures of crime for each of a minimum of the area types (treatment, control, and catchment areas), the review produced odds ratio effect sizes that were used in a meta-analysis. This summarized the effectiveness of the policing interventions and the displacement diffusion effect, respectively. Other tests assessed the effects of study design, intervention type, size of intervention, and publication bias. A quantitative analysis of the 16 studies summarized the mean Weighted Displacement Quotient, a measure developed in earlier work by two of the study's authors. A proportional chance analysis examined increases and decreases in crime in treatment and catchment areas (nearby areas most likely to receive any crime displacement) for the 36 studies for which count data were available. This analysis did not require data to be available for a control area. Appended supplementary information, including brief descriptions of each of the eligible studies reviewed