Evidence-Based Policing Matrix
Neighborhood – Heaton et al. (2016)
Study Reference:
Location in the Matrix; Methodological Rigor; Outcome:
Neighborhood; General; Proactive; Rigorous; Mixed findings
What police practice or strategy was examined?
The study examined the impact of the University of Chicago Police Department (UCPD), a privately funded university police force, on crime. The UCPD expanded its primary jurisdiction to areas surrounding its campus between 2001 and 2012, providing extra police presence and services in those areas in addition to regular patrol conducted by the Chicago Police Department (CPD). This study evaluates the impact of the expansions in 2001 and 2004 on crime in these expansion zones.
How was the intervention evaluated?
As a result of the expansions, 52 census blocks became part of the jurisdictions of both UCPD and CPD in October 2001, and 77 in April 2004. These constituted the treatment blocks. The control area was defined as the 1,954 census blocks surrounding UCPD jurisdictions where the UCPD never had jurisdiction. Using a difference-in-difference approach, the authors examined changes in the average monthly crime rates before and after the expansions in the treatment vs. the control areas. The study also evaluated the long-term impact of UCPD with a regression discontinuity design focused on differences in crime combined over a long period in areas immediately surrounding the UCPD’s patrol border to minimize any unobserved differences between the treatment and control areas.
What were the key findings?
Results of the difference-in-difference analysis suggest that there was no statistically significant short-term effect on monthly crime identified in the areas annexed by the UCPD. However, analyses focused on longer-term effects based on areas immediately surrounding the UCPD’s patrol border suggest that blocks patrolled only by CPD had 55% more crimes than those patrolled by the UCPD from April 2004 through May 2012. The effect is statistically significant. Subtype analyses indicate that the effect was significant for overall violent crime, but not for property crime or the subset of violent crime committed in public spaces.
What were the implications for law enforcement?
The authors suggest that these contradictory results appear to be a consequence of a delayed effect of private police on crime. Introducing private police to a patrol area initially had no measurable effect on crime, yet after sufficient time had passed, the presence of private police was associated with meaningful reductions in crime. This suggests permanent private police can be a cost-effective investment in the long term and also provides evidence that campus police departments should be encouraged to patrol not only on campus, but in areas surrounding the university.
Where can I find more information about this intervention, similar types of intervention, or related studies?