Evidence-Based Policing Matrix
Neighborhood – Berk & MacDonald (2010)
Study Reference:
Location in the Matrix; Methodological Rigor; Outcome:
Neighborhoods; Focused; Proactive; Rigorous; Effective
What police practice or strategy was examined?
This study examined the crime reduction benefit of the Safer Cities Initiative that targeted homeless encampments in downtown Los Angeles. Highly concentrated homeless populations downtown, especially in the “Skid Row” area, were believed to be linked with high rates of street crime and disorder. To address this, 50 officers in the Central Division implemented a series of tactics in the area on and around Skid Row, including breaking up homeless encampments, issuing citations, making arrests, maintaining a visible presence and performing order maintenance. The program ran from August 2006 to the end of 2007. Before the project, the LAPD conducted a pilot program using similar strategies in September 2005. This study evaluated the impact of these two programs on nuisance crime, violent crime, and property crime.
How was the intervention evaluated?
The study evaluated the intervention using a longitudinal quasi-experimental design, looking at the three crime types by week from January 2000 to December 2007 in both the target and comparison group. The four divisions bordering the target division served as non-equivalent comparison groups. The authors also tested for displacement and diffusion effects of the interventions in the four adjacent police divisions.
What were the key findings?
The authors found modest but meaningful reductions for all three types of crime that can be attributed to both the pilot program and the formal intervention. The Skid Row homeless encampments were completely cleared. Crime also decreased in adjacent divisions after the interventions, which may suggest spillover effects, but the evidence on such effects is less conclusive since information is lacking regarding what the police may have done in those areas.
What were the implications for law enforcement?
The authors suggest that geographically targeted police interventions can lead to significant crime prevention benefits, with no evidence of crime displacement. Targeted police actions can reduce crime associated with homeless encampments, but, at the same time, it is necessary to address the root causes of homelessness.
Where can I find more information about this intervention, similar types of intervention, or related studies?