No Effects - One study
Randomized Controlled Trial
Date: This profile was posted on April 25, 2016
This strategy is aimed at reducing crime at violent-crime hot spots in Philadelphia, Pa., through police foot patrols. It involved having veteran officers patrol areas (an average of 3 miles of streets) during one shift per day. This program is rated No Effects. Relative to the control areas, increasing foot patrols at violent-crime hot spots had no impact on violent crimes, violent felonies, or citizens’ perceptions of crime and safety.
This police foot patrol strategy involved veteran officers patrolling an area of approximately 3 miles during one shift per day. It is rated No Effects. Compared with the control areas, there was no impact on violent crimes or citizens’ perceptions of safety in hot spots.
NOTE: CrimeSolutions.gov features two similar, but distinct foot patrol programs that were implemented in Philadelphia. (The other is Police Foot Patrol–Philadelphia 2009.) These strategies are listed separately because of key differences in how each strategy was implemented. See “Other Information” below for a more detailed discussion of these differences and a link to the other rated program.
The Philadelphia Policing Tactics Experiment was a randomized controlled field experiment of three approaches to hot spots policing: offender-focused policing, foot patrol, and problem-oriented policing. The foot patrol portion of the intervention, implemented in 2010, was designed to reduce violence at violent-crime hot spots. It was expected that police could efficiently reduce the number of violent crimes in the city by targeting the areas in Philadelphia where the most violent crimes occurred. The idea was to increase officer presence at hot spots by implementing foot patrols that would enable officers to become familiar with the routines of residents. The foot patrols were intended to prevent crime from occurring and to help officers apprehend suspects should a crime occur.
In Philadelphia, foot patrol occurred 5 days per week over the course of 12 weeks. Pairs of police officers patrolled the targeted areas for at least 8 hours each day. Officers with varying years of experience were involved in the foot-patrol intervention. A little more than half were assigned by their supervisors because they had the necessary skills and experience; the other half volunteered. District captains had discretion over how many officers would patrol, which days and times officers would patrol, and other operational decisions. The timing of each shift varied, depending on the nature of crime in the location. For example, some officers assigned to foot patrols worked during the day shift (between 7 a.m. and 6 p.m.), while some worked during the evening shift (between 4 p.m. and 2 a.m.); a few officers alternated between day and night shifts weekly. The hot spots targeted by the foot patrols encompassed an average of 3 miles of streets and 23.5 intersections.
Officers were assigned to one foot patrol area so that the same officers would patrol throughout the entire experiment. Some officers reported implementing a variety of problem-oriented responses as they were patrolling their assigned areas, such as clearing trash in alleyways or parks where guns were previously hidden. Other officers reported using more traditional responses during foot patrol, such as making arrests and performing field stops.
Deterrence theory serves as the underlying premise of the idea that increasing police presence in hot spots through targeted foot patrols can reduce crime. When potential offenders view the police in their neighborhood, they perceive the risk of apprehension as greater than if a police officer is not present (Groff et al. 2015). Specific individuals are not targeted, but if a police officer patrols the neighborhood frequently and becomes familiar with the residents and local patterns of behavior, it is more likely that he or she will notice something or someone out of the ordinary and be able to identify and arrest criminals. As such, more visible police presence increases the costs associated with committing crimes (Police Foundation 1981).
Groff and colleagues (2015) found that areas in Philadelphia identified as crime hot spots that received the foot patrol intervention did not experience a statistically significant decrease in violent crime, relative to the control areas.
In addition, there was no statistically significant difference in violent felony counts.
Ratcliffe and colleagues (2015) reported no statistically significant differences in how citizens residing in hot spots viewed crime and disorder in their areas before and after foot patrol was implemented. Residents did not feel safer, perceive different amounts of crime or disorder, or view the police more positively or negatively.
Groff and colleagues (2015) evaluated the effects of foot patrols as part of the Philadelphia Policing Tactics Experiment. This study comprised evaluations of three tactics: foot patrol, problem-oriented policing, and offender-focused policing. As part of the experiment, intelligence analysts identified 81 violent crime hot spots within Philadelphia and police commanders determined which one of the three tactical approaches would be most appropriate to employ at each hotspot. Commanders chose 27 hot spots for each of the three interventions. Hot spots in each of these groups were randomly assigned to treatment and control categories. With regard to the foot patrol intervention, 20 hot spots received increased foot patrol for 12 weeks and seven hot spots served as control areas. Control areas received no additional police attention; officers patrolled as usual. The treatment and control areas were equivalent at baseline due to randomization.
The primary outcome of interest was change in violent crime during the intervention period, which was examined using repeated-measures multilevel models and controlling for seasonality and the size of the hotspot. Contrast coding was used to examine crime rates during the intervention period rather than before or after the tactics were instituted. Violent crime was measured in two ways: violent felonies and all violent crimes. Violent crimes included all homicides, robberies, and aggravated assaults (simple assaults were excluded). The Philadelphia Police Department provided official data on the number of violent crimes biweekly during the study period. Spatial displacement of violent crimes in areas surrounding the treatment hot spots was also measured.
Ratcliffe and colleagues (2015) examined the extent to which the Philadelphia Policing Tactic Experiment influenced citizens’ perceptions of the police. The researchers administered mail surveys 90 days before the tactics were implemented and 90 days afterwards. The surveys gauged how offender-focused policing, foot patrol, and problem-oriented policing altered perceptions of crime, safety, disorder, and satisfaction with the police in the 81 hot spots.
Any taxable residence within the hotspot was eligible to receive the survey. With regard to foot patrol hot spots specifically, 1,860 surveys were sent to addresses in the 20 hot spots before or after the intervention period. A total of 1,855 surveys were sent to residents in the control areas. A total of 160 surveys from foot patrol hot spots and 159 from control areas were returned before the policing tactics were implemented. Post-intervention, 148 surveys were returned from the foot patrol areas and 177 from control residences, amounting to a response rate of 9 percent. Due to high non-response bias, citizens who returned the survey were likely not representative of all citizens in the intervention and control areas. Ordinary least squares (OLS) regressions were used to estimate the impact of the policing tactics on changes in community perceptions of crime, disorder, safety, and satisfaction with the police.
A considerable limitation of this study was the inability to match survey responses to specific households before and after the policing tactics were implemented. The study authors suggested that it was unlikely that the responses were attained from the same residents at both times, making it difficult to know whether the dependent variables captured changes in perceptions or reflected the perceptions of two different groups at two different times.
There is no cost information available for this program.
To ensure that police officers were patrolling in their designated areas in Philadelphia for the correct amount of time, the research staff reviewed incident databases, the daily logs where officers recorded their activity, and in some cases also observed officers. At least one foot patrol officer from each hotspot was interviewed and asked about compliance with the foot patrol intervention.
The incident databases, daily logs, and interviews showed that most officers patrolled in pairs and worked one shift, 5 days per week. The information also showed that about one third of the officers assigned to foot patrol coordinated with other agencies to solve problems. Some officers also focused on specific problem people in their assigned area (Groff et al. 2015)
The foot patrol intervention of the Philadelphia Policing Tactics Experiment implemented in 2010, which is described here, is distinct from the foot patrol intervention described in the Police Foot Patrol–Philadelphia 2009 intervention (https://www.crimesolutions.gov/ProgramDetails.aspx?ID=234). Although both experiments employed foot patrols at hot spots in Philadelphia, there were a number of important differences.
First, the two experiments involved police officers with different levels of experience. The Philadelphia Policing Tactics Experiment foot patrol in 2010 involved veteran officers, whereas the Philadelphia Foot Patrol Experiment in 2009 involved rookie officers who had just graduated from the police academy. Goff and colleagues (2015) noted that veteran officers appeared to be less aggressive in their enforcement, compared with rookie officers.
Second, there were differences in the length of time the foot-patrol interventions were implemented. The Philadelphia Policing Tactics Experiment foot-patrol intervention took place over 12 weeks in 2010. By comparison, the Philadelphia Foot Patrol Experiment was conducted over 22 weeks in the beginning of 2009.
Another difference was the amount of time officers spent patrolling targeted areas. In the 2010 experiment, one pair of officers worked one shift, resulting in at least 8 hours of patrol time per day. In the 2009 experiment, two pairs of officers patrolled areas, resulting in 16 hours of patrol time per day.
Finally, the area of the targeted hot spots differed by experiment. In the 2010 experiment, the hot spots encompassed an average of 3 miles of streets and 23.5 intersections, whereas the hot spots targeted by the 2009 experiment encompassed an average of 1.3 miles of streets and 14.7 intersections.
These factors may explain why significant effects on crime were found during the 2009 experiment, but not during the 2010 experiment (Ratcliffe et al. 2011; Ratcliffe et al. 2015).
Evidence-Base (Studies Reviewed)
These sources were used in the development of the program profile:Study 1
Groff, Elizabeth R., Jerry H. Ratcliffe, Cory P. Haberman, Evan T. Sorg, Nola M. Joyce, and Ralph B. Taylor. 2015. “Does What Police Do at Hot Spots Matter? The Philadelphia Policing Tactics Experiment.” Criminology
Ratcliffe, Jerry H., Elizabeth R. Groff, Evan T. Sorg, and Cory P. Haberman. 2015. “Citizens’ Reactions to Hot Spots Policing: Impacts on Perceptions of Crime, Disorder, Safety, and Police.” Journal of Experimental Criminology
These sources were used in the development of the program profile:
The Police Foundation. 1981. The Newark Foot Patrol Experiment
. Washington, D.C.: The Police Foundation.
Ratcliffe, Jerry H., Travis Taniguchi, Elizabeth R. Groff, and Jennifer D. Wood. 2011. “The Philadelphia Foot Patrol Experiment: A Randomized Controlled Trial of Police Patrol Effectiveness in Violent Crime Hotspots.” Criminology
Following are CrimeSolutions.gov-rated practices that are related to this program:Hot Spots Policing
Used by many U.S. police departments, hot spots policing strategies focus on small geographic areas or places, usually in urban settings, where crime is concentrated. The practice is rated Effective. The analysis suggests that hot spots policing efforts that rely on problem-oriented policing strategies generate larger crime reduction effects than those that apply traditional policing strategies in crime hot spots.Evidence Ratings for Outcomes:
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