Program Profile: Directed Patrol and Self-Initiated Enforcement in Hot Spots (St. Louis, Missouri)

This experiment assessed the impact of two hot spots policing tactics on firearm violence. The program is rated Promising. Compared with comparison hot spots, hot spots that received self-initiated enforcement experienced a statistically significant reduction in firearm assault rates, but there were no statistically significant differences for hot spots that received directed patrol. There was no statistically significant effect on firearm robbery rates between treatment and comparison hot spots

A Promising rating implies that implementing the program may result in the intended outcome(s).

Program Goals

In 2012, the St. Louis Metropolitan Police Department (SLMPD) implemented an experiment to assess the impact of different hot spots-policing tactics (directed patrol and self-initiated enforcement) on firearm violence. The experiment was implemented as part of a “Public Safety Partnership,” which included the SLMPD, the mayor’s office, and researchers at the University of Missouri, St. Louis. The SLMPD’s Crime Analysis Unit (CAU), alongside university researchers, developed the experiment, which was designed to last for 9 months.

Although hot spots policing, in general, includes the increase of police presence in an area where crime typically occurs, there are different tactics that can be used by the officers to specifically address crime. Therefore, the overall goal of this experiment was to investigate the relative effectiveness of two different tactics: directed patrol and self-initiated enforcement.

Target Sites

The CAU selected 46 geographic areas in St. Louis with the highest amount and concentration of firearm violence and robberies occurring over several months during the year prior to the experiment. Firearm violence was determined by counts of homicides and nondomestic aggravated assaults committed with a firearm. From this list, the CAU selected four areas within each of the eight districts with the highest amount and concentration of firearm violence.

Program Activities

Officers who were assigned to directed patrol were instructed to patrol slowly through the hot spots area and avoid engaging in self-initiated contact, unless a crime was in progress, or the safety of a citizen or fellow officer was in jeopardy.

Conversely, officers who were assigned to self-initiated enforcement tactics were also instructed to patrol slowly through the hot spots area, but were also told to engage in forms of self-initiated activity. Self-initiated activity was defined as arrest, pedestrian checks, building checks, occupied vehicle checks, unoccupied vehicle checks, foot patrol, and problem solving. The experiment was limited to evening shifts (3:00 – 11:00 p.m.) and overnight shifts (11:00 p.m. – 7:00 a.m.), when the frequency of firearm violence was the greatest.

Study 1

To determine the effectiveness of different hot spots-policing tactics (i.e., directed patrol in hot spots areas and self-initiated enforcement in hot spots areas), Rosenfeld and colleagues (2014) used a randomized controlled experimental design with two treatment areas (directed patrol and self-initiated activity) and one comparison area. Officers who were assigned to the directed patrol areas (Treatment 1) were instructed to patrol slowly through the hot spots area and avoid engaging in self-initiated contact, unless a crime was in progress or the safety of a citizen or fellow officer was in jeopardy. Officers who were assigned to the self-initiated enforcement areas (Treatment 2) were also instructed to patrol slowly through the hot spots area but were also told to engage in one or more forms of self-initiated activity. The officers assigned to the comparison areas were not given special instructions and were not notified of the experiment.

The St. Louis Metropolitan Police Department’s (SLMPD)’s Crime Analysis Unit (CAU) and researchers from the University of Missouri, St. Louis used the ESRI ArcMap geospatial mapping to identify hot spots of firearm violence across street segments in each of the eight participating police districts during the year prior to the intervention. Hot spots areas were identified based on the allocation of homicides, firearm assaults, and firearm robberies. Areas whose crime concentration was two standard deviations above the mean crime concentration for that area were analyzed by summing the number of violent crime incidents per street segment. Street segments with numerous crime incidents the previous year were included in the experiment, which resulted in 32 hot spots within the eight police districts (four hot spots within each district). The four hot spots within each police district were then randomly assigned to the treatment and comparison areas. For example, in one district, one hot spot would receive Treatment 1, one hot spot would receive Treatment 2, and the remaining two hot spots would be assigned to the comparison areas.

The outcomes of interest were firearm assault rates and firearm robbery rates. A difference-in-difference (DID) design was used to contrast the difference in outcomes between the treatment conditions and comparison areas both before and during the intervention. A DID design also allowed the researchers to determine the differences between two different hot spots?policing tactics (directed patrol and self-initiated enforcement). No subgroup analysis was conducted.

These sources were used in the development of the program profile:

Following are CrimeSolutions-rated programs that are related to this practice:

Hot Spots Policing

Hot spots policing strategies focus on small geographic areas or places, usually in urban settings, where crime is concentrated. Through hot spots policing strategies, law enforcement agencies can focus limited resources in areas where crime is most likely to occur. This practice is rated Effective for reducing overall crime and rated Promising for reducing violent, property, public order, and drug and alcohol offenses.

Evidence Ratings for Outcomes

	Crime & Delinquency - Multiple crime/offense types
	Crime & Delinquency - Violent offenses
	Crime & Delinquency - Property offenses
	Crime & Delinquency - Public order offenses
	Crime & Delinquency - Drug and alcohol offenses

Why might a practice's outcome ratings differ from the ratings of specific programs encompassed by that practice?