Rosenfeld, R., Deckard, M. J., & Blackburn, E. (2014). The effects of directed patrol and self-initiated enforcement on firearm violence: a randomized controlled study of hot spot policing. Criminology, 52(3), 428-449.
Location in the Matrix; Methodological Rigor; Outcome:
Micro places, Focused, Proactive; Very Rigorous; Mixed findings
What police practice or strategy was examined?
The study examined directed patrol and enforcement activities conducted at firearm violence hot spots in St. Louis, Missouri. Officers were instructed to patrol their assigned hot spots at least three times during an 8-hour duty shift and to remain in that area for approximately 15 minutes each time. During that 15 minutes, they were instructed to engage in one or more self-initiated activities, including arrests, pedestrian checks, building checks, occupied vehicle checks, unoccupied vehicle checks, foot patrol, and other problem solving techniques. The intervention was restricted to the evening (3 p.m. to 11 p.m.) and overnight shifts (11 p.m. to 7 a.m.) when firearm violence was most frequent.
How was the intervention evaluated?
Four hot spots with the highest frequency and spatial concentration of firearm violence in each of the eight districts were randomly assigned, with one assigned to the directed patrol with enforcement activities condition (the condition described here), one to the directed patrol only condition, and two to the control condition. No instructions were given to officers in the control areas. Firearm aggravated assault and firearm robbery incidents were measured 9 months prior to the intervention and during the 9 months of the intervention at both treatment and control sites. In addition, the study tested displacement to other types of crime (non-firearm violent crime), other time periods (during the day shift), and surrounding areas (within a 500-ft radius of the hot spot boundaries).
What were the key findings?
Directed patrol with enforcement activities reduced total firearm violence by 20% at the treatment area relative to the control areas. Firearm assaults decreased by about 55%, while there was no significant change in firearm robbery. These effects were likely attributable to the increased certainty of arrest and the increase in occupied vehicle checks that resulted from the self-initiated activities. No displacement was found for firearm assault.
What were the implications for law enforcement?
The authors suggest that enforcement activities, in particular increasing the certainty of arrest and conducting occupied vehicle checks, can reduce firearm assault without displacement , but they do not seem to have the same impact on firearm robbery.
Where can I find more information about this intervention, similar types of intervention, or related studies?