Weisburd, D., Groff, E. R., Jones, G., Cave, B., Amendola, K. L., Yang, S. M., & Emison, R. F. (2015). The Dallas patrol management experiment: can AVL technologies be used to harness unallocated patrol time for crime prevention?. Journal of Experimental Criminology, 11(3), 367-391.
Location in the Matrix and Methodological Rigor:
Micro places, General, Proactive; Rigorous; Effective
What police practice or strategy was examined?
The study examined whether information on police patrol drawn from automatic vehicle location (AVL) systems could be used to increase the amount of directed patrol time at (1) high-crime police beats and (2) crime hot spots, and whether such increases would lead to reductions in crime. Summarized here are the findings from the hot spot-level analysis. Police agencies often use crime counts at beats or hot spots to allocate patrol resources for directed patrol. However, in this study, commanders were also given weekly reports that included the following information for both beats and hot spots within those beats: the amount of attention each commander had requested for those areas from the previous week; the amount of patrol time received in each type of area as measured by AVL; and more specifically, the amount of patrol time in each area that was “unallocated” to a given call for service as measured by AVL. Managers then used the reports in weekly Compstat meetings held within each division, during which emerging problems and hot spots were identified for increased attention. The study tested whether supervisor knowledge of unallocated patrol time can be successfully used to redirect resources to crime hot spots and therefore deter future crime.
How was the intervention evaluated?
Utilizing a block-randomized experimental design, 232 police beats were randomly allocated to an experimental or control condition. The information described above was provided to commanders in the experimental beats (and hot spots within those beats) but not to the control condition where standard police patrol was implemented. A composite measure of crime based on incident data was used that included a range of violent and property offences. Over a 13-week period, assigned patrol time, unallocated patrol time, total patrol time, and crime were tracked and compared at crime hot spot grids (N=1006).
What were the key findings?
Compared with the control group, the treatment hot spot grids experienced significant increases in unallocated patrol time (27%) and total patrol time (20%), and a decrease in crime (21%).
What were the implications for law enforcement?
The authors argue that police managers can use information generated from AVL to increase directed patrol time at crime hot spots and that this can reduce crime at those hot spots (but not necessarily at the beats that house those hot spots).
Where can I find more information about this intervention, similar types of intervention, or related studies?
Dallas AVL study at the beat level (link coming soon)