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Program Profile: Police Foot Patrol–Philadelphia 2009

Evidence Rating: Effective - One study Effective - One study

Date: This profile was posted on April 18, 2012

Program Summary

This program used a foot patrol to reduce violent crime in hot spots in Philadelphia, Pa. It involved having rookie officers patrol areas (an average of 1.3 miles of streets) during two shifts per day. This program is rated Effective. There were significant reductions in reported violent crime, although the effect seemed to fade once officers were removed from their targeted beats.

This program’s rating is based on evidence that includes at least one high-quality randomized controlled trial.

Program Description

NOTE: features two similar but distinct foot patrol programs that were implemented in Philadelphia. (The other is Police Foot Patrol–Philadelphia 2010.) 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.

Program Goals
Late during the first decade of the 21st century, violent crime levels rose to epic proportions in Philadelphia, PA. As of 2008, there had been more than a hundred shootings recorded in the city each month since 2002. Further, crime data indicated that a noticeable and consistent cycle of increased violent crime occurred during summer months. Violent crime had become so rampant that the community had begun to view it as a public health threat, placing pressure on law enforcement to address the issue.

In response, the Philadelphia Police Department developed the Philadelphia Foot Patrol strategy in 2009, which used proactive, nonthreatening, and community-oriented approaches to local policing. The strategy combined these approaches with techniques borrowed from hot spots policing, disseminating foot patrol to specific high-crime locations. The overall goal was to create significant reductions in violent crime by increasing officer presence in high-crime locations, specifically during the summer months.

Target Sites
The strategy concentrated on implementing foot patrol at certain addresses, street segments, and clusters of microspatial units with high levels of violent crime in Philadelphia.

Program Activities
The strategy emphasized increasing police visibility and presence in high-crime locations and thus did not concentrate on specific activities of officers while on patrol. Officers patrolled their areas 5 days per week for about 16 hours a day. Those involved in the foot patrol intervention had recently graduated from the police academy. In each target area, two pairs of rookie officers were assigned to engage in intensive foot-patrol policing. Pairs of police officers patrolled the targeted areas for at least 8 hours each day. The officer pairs were assigned to either a morning (10 a.m. to 6 p.m.) or an evening shift (6 p.m. to 2 a.m.) from Tuesday through Saturday nights. The pairs alternated morning and evening shifts every other week. Thus, there were areas were not covered by foot patrols from 2 a.m. to 10 a.m. each day, and from 2 a.m. Sunday through 10 a.m. Tuesday each week. The hot spots targeted by the foot patrols encompassed an average of 1.3 miles of streets and 14.7 intersections.

During the implementation of the strategy, rookie officers engaged in various types of activities while patrolling assigned locations. Some officers engaged in extensive community-oriented work, speaking to community members and visiting child care centers and juvenile hangouts. Other officers took a more crime-oriented approach to their patrol assignment, stopping vehicles at stop signs and intersections, and interviewing pedestrians. In sum, the strategy used a meticulous analysis of the distribution of violent crime across locations, to successfully employ visible presence of officers in the most problematic areas.

Key Personnel
Proper implementation of the strategy relied on coordinating various divisions within the Philadelphia Police Department to accurately identify high-crime locations and coordinate the assignment of officers to designated areas. It was also necessary for patrol officers to maintain a visible presence in assigned patrol locations.

Program Theory
The Philadelphia Foot Patrol strategy used a spatially oriented approach that borrowed ideas from several complementary criminological theories, including rational choice, routine activities, and environmental criminology. Spatially oriented crime control programs aim to make changes in areas that provide crime opportunities, to create constraints on criminal behavior. Such an approach includes a concentration on deterrence in specific areas, to increase certainty of disruption, apprehension, and arrest using enhanced visibility of police. The rational choice theory posits that the decision to commit a crime is made rationally by an offender, that it is a deliberate decision made after judging that the potential benefits of the crime outweigh the potential risks. The routine activities theory posits that a criminal act occurs when there is a convergence of a suitable target in the absence of a capable guardian (Sherman, et al. 1989). This complements rational choice because, when the opportunity to commit crime is presented, the offender is more likely to make the choice to offend (Akers 1990).

The role of place is introduced by environmental criminology, also known as crime pattern theory, which suggests that a reduction in offending will occur if characteristics of an environment are altered to make the location less appealing to criminals (Santos 2015). Through a combination of rational choice, routine activities, and environmental criminology, a theory arises that making changes to an environment can have a significant impact on a potential criminal’s decision to commit crimes in that area. Therefore, the foot patrol strategy followed from the premise that increasing officer visibility in high-crime locations would render such locations less optimal for criminal offending, leading to a deterrent effect and a reduction in violent crime.

Evaluation Outcomes

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Study 1
Reported Violent Crime
Ratcliffe and colleagues (2011) found that the target areas experienced a relative 23 percent statistically significant reduction in reported violent crime in comparison with the control areas. These effects were most noticeable in target areas with the highest levels of preintervention violent crime, as target areas in the top 40 percent on pretreatment violent crime counts had significantly less violent crime during the operational period. These findings suggest that targeted foot patrols in violent crime hot spots can significantly reduce violent crime levels, as long as a threshold level of violence exists initially.

Displacement and Diffusion Effects
An analysis of displacement and diffusion effects indicated a reduction of 90 crimes in the target areas, which was offset by an increase of approximately 37 offenses occurring in buffer zones surrounding target areas—leading to an overall net effect of 53 violent crimes prevented across the city of Philadelphia. The analysis indicates significant evidence of displacement of violent crime to nearby locations; however, these effects were outweighed by direct benefits seen in target areas.

Incident Type Frequency
The frequency of all incident types increased during the operational period, compared with pretreatment levels. Results indicate that the foot patrol officers (as identified by their radio call signs) contributed substantially to the rise in proactive police activity observed in treatment areas. In treatment areas, pedestrian stops by police officers increased by 64 percent, vehicle stops increased by 7 percent, police disruptions of disturbances increased by 47 percent, disruptions of narcotics incidents increased by 15 percent, and disruptions of disorder incidents increased by 57 percent. Finally, arrests increased by 13 percent. Based on these increases, it can be inferred that the proactive activities used in walking patrol increased the enforcement of minor violations. It is possible that such proactive policing techniques helped increase police visibility in treatment locations, thereby contributing to reductions in violent crime.

Study 2
Sorg and colleagues (2013) found significant differences between the treatment and control areas on violent crime counts while police officers patrolled targeted areas in Philadelphia. However, once officers were removed from the target areas, there was no significant difference in levels of violence between the treatment and control areas.

Phase 1 and Phase 2 Violent Crime Counts (Treatment Effects)
During Phase 1, the treatment beats targeted by the foot patrols had significantly lower expected violence crime counts compared with the control beats (an average of about 16 percent lower). Similarly, during Phase 2, the treatment beats targeted by the foot patrols had significantly lower expected violence crime counts compared with the control beats (an average of about 20 percent lower)

Phase 1 and 2 Violent Crime Counts (Posttreatment Effects)
There were no significant differences between the treatment and control areas on levels of violence during the posttreatment period, suggesting the foot patrol did not have lasting impacts on crime once the officers were removed from the targeted beats.

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Evaluation Methodology

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Study 1
Ratcliffe and colleagues (2011) conducted a randomized controlled trial to assess the impact of the Philadelphia Foot Patrol strategy in reducing crime during the summer, when violent crime levels in Philadelphia, PA, tended to peak. The experiment was intended to isolate the specific impact of foot patrol as a crime-reduction strategy in order to examine its feasibility to create meaningful reductions in violent crime. The evaluation took place during peak summer months in 2009.

The study began with the identification of hot spots using data from the incident (INCT) database of the Philadelphia Police Department for 2006, 2007, and 2008. High-crime areas identified by the database were then assigned to spatial units, producing 120 total locations for inclusion in the experiment. A randomized block design was then used to separate the locations into two groups; 60 were assigned as control locations, and 60 were assigned to receive treatment. Treatment locations were assigned two pairs of officers to engage in intensive foot patrol policing, while control locations received no foot patrol policing. The officer pairs were assigned either a morning (10 a.m. to 6 p.m.) or an evening shift (6 p.m. to 2 a.m.) that they policed Tuesday through Saturday nights. The pairs alternated morning and evening shifts every other week. This meant that the areas were not assigned foot patrols from 2 a.m. to 10 a.m. each day, and from 2 a.m. Sunday right through to 10 a.m. Tuesday each week.

A comparison of crime frequency in both the 60 target areas and the 60 control areas before and during the operational period was used to determine the impact of the strategy. Data from the immediate 3 months before the start of the experiment was compiled for use as a measure for a pretreatment period. The operational period of the experiment was executed using two phases. Phase 1 commenced on March 31, 2009, with officers in 24 foot patrol areas. Phase 2 commenced on July 7, 2009, and totaled 36 patrolled areas. Over the first 12 weeks of each phase combined, this theoretically provided for 57,600 hours of foot patrol activity. A linear regression model was used to determine the statistical significance of changes in violent crime for both groups between pretreatment and operational levels. Analyses of displacement and diffusion effects and incident type frequency were used to supplement the analysis of crime trends for the experiment.

  • Reported violent crime. Data was provided by the Philadelphia Police Department from the INCT database, which assigns a Uniform Crime Report classification to all entries. Violent crime was defined as criminal homicide, all robberies (except cargo theft), and a majority of aggravated assaults. Violent crimes that were likely to take place indoors and were not expected to be prevented by foot patrol, such as rape, were excluded from the analysis.

  • Displacement and diffusion effects. The total net effect of the operation was calculated to assess the possibility that the strategy displaced violent crime to nearby areas, or that violent crime reductions were diffused to nearby areas. This was examined using an analysis of effects in nearby buffer areas, which encompassed the area of about 1,000 feet around target sites. Effects were calculated by examining the ratio of the crime reduction in the target areas after factoring in the general change in the control areas and then taking into consideration any displacement or diffusion to the buffer area.

  • Incident type frequency. The frequency of various minor criminal incidents was measured to examine the impact of increased proactive police activity after implementation of the foot patrol strategy. Such incidents were chosen as measures because of the likelihood that they would be handled by a patrol officer, as opposed to a call for service. A pedestrian stop was recorded when an officer conducted a field interview, a stop-and-frisk, or a search of suspect in the street. A vehicle stop was recorded when an officer pulled over an occupant in a vehicle. Disturbances were recorded for incidents that involved police disruption of rowdy behavior. Incidents involving narcotics were also recorded. Disorder incidents included public order offenses such as prostitution, public drunkenness, loitering, or violation of city ordinances. Arrests were also recorded, to provide possible indications of proactive police work.

Study 2
Sorg and colleagues (2013) conducted a randomized experiment to examine the longitudinal deterrent effects of foot patrols in violent crime hot spots. In 2009, 240 rookie police officers were assigned to 60 of Philadelphia’s violent hot spots soon after their graduation from the police academy. The officers patrolled in pairs on a day (10 a.m. to 6 p.m.) and night (6 p.m. to 2 a.m.) night shift, 5 days a week (Tuesday through Saturday). Two phases were deployed to coincide with academy graduation dates. Phase 1 deployed March 31, 2009 and ended August 31, 2009. Phase 2 deployed July 7, 2009, and ended September 28, 2009.
Researchers identified experimental areas by reviewing violent crime event data that included homicide, aggravated assault, and robbery. This information was taken from the Philadelphia Police Department’s incident database from 2006–2009. Police leadership agreed to 129 foot beats for the study. From this list, the researchers adjusted beats that were too large or overlapped with other beats, and dropped the four lowest crime beats, which resulted in a total of 120 experimental beats (60 target foot beats and 60 control foot beats).
To measure displacement, buffer zones were drawn around treatment locations, which measured displacement. Buffer zones averaged 2.8 miles of street, and could not overlap with the experimental areas and could not cross physical barriers. Overall, 55 buffer zones were created across10 foot patrol areas.
To assess the effects of the Philadelphia Foot Patrol experiment over time and at its conclusion, multilevel growth curve models were used to analyze the outcome data. Four separate modes were run: 1) model estimating treatment effects; 2) model estimating initial deterrence decay; 3) model estimating posttreatment effects; and 4) model estimating residual deterrence decay. This review focused on the treatment effects and posttreatment effects models.
The outcome of interest was violent crime counts in each of the treatment and control hot spots aggregated to 2-week time periods. The same violent crime incident categories were used to identify violent crime hot spots and  the outcome variables: homicide, robbery (excluding cargo thefts), and pertinent classifications of aggravated assaults (excluding categories that foot patrols are unlikely to affect, such as assaults against police or assaults in schools). Data from the Philadelphia Police Department’s incident database were taken from approximately 1 year before Phase 1 began (April 1, 2008).
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There is no cost information available for this program.
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Implementation Information

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Patrol officers were required to receive specialized training and orientation to become familiarized with assigned locations. Officers received a 1-week orientation at the police district of their specific foot patrol location, after which they spent an initial period of a few weeks in and around their beat with an experienced officer. In addition, all patrol officers were provided with an initial criminal intelligence brief on their foot patrol area by the criminal intelligence unit. This training was necessary to ensure that officers were familiar with the community and environment where they were to patrol.
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Other Information (Including Subgroup Findings)

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This foot patrol intervention, implemented as the Philadelphia Foot Patrol Experiment in 2009, which is described here, is distinct from the foot patrol intervention described in the Police Foot Patrol–Philadelphia 2010 intervention( 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).
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Evidence-Base (Studies Reviewed)

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

Study 1
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 49(3):795–831.

Study 2
Sorg, Evan T., Cory P. Haberman, Jerry H. Ratcliffe, and Elizabeth R. Groff. 2013. “Foot Patrol in Violent Crime Hot Spots: The Longitudinal Impact of Deterrence and Posttreatment Effects of Displacement.” Criminology 51(1):65–101.
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Additional References

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

Akers, Ron L. 1990. “Rational Choice, Deterrence, and Social Learning Theory in Criminology: The Path Not Taken.” Criminology 81(3):653–76.

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 53(1):21–53.

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 11:393–417.

Santos, Rachel Boba. 2015. “Routine Activity Theory: A Cornerstone of Police Crime Analyst Work.” In M. Anderesen and G. Farrell (eds.). Developments in Crime Scene: The Role and Influence of Routine Activity Theory. New York, NY: Palgrave Macmillan.

Sherman, Lawrence W., Patrick R. Gartin, and Michael E. Buerger. 1989. "Hot Spots of Predatory Crime: Routine Activities and the Criminology of Place." Criminology 27(1):27–56.

Temple University. N.d. "The Philadelphia Foot Patrol Experiment." Ambler, Pa.: Temple University College of Liberal Arts, Department of Criminal Justice.
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Related Practices

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Following are 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:
Effective - One Meta-Analysis Crime & Delinquency - Multiple crime/offense types

Street-Level Drug Law Enforcement
This practice includes targeted-policing approaches for reducing drug and drug-related offenses. This practice is rated Promising in reducing reported, drug-related calls for services and offenses against persons. This practice is rated No Effects in reducing reported property offenses, public order calls for service, and total offenses.

Evidence Ratings for Outcomes:
Promising - One Meta-Analysis Crime & Delinquency - Drug and alcohol offenses
Promising - One Meta-Analysis Crime & Delinquency - Violent offenses
No Effects - One Meta-Analysis Crime & Delinquency - Property offenses
No Effects - One Meta-Analysis Crime & Delinquency - Public order offenses
No Effects - One Meta-Analysis Crime & Delinquency - Multiple crime/offense types
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Program Snapshot

Gender: Both

Geography: Urban

Setting (Delivery): Other Community Setting, High Crime Neighborhoods/Hot Spots

Program Type: Community and Problem Oriented Policing, Foot Patrol, Situational Crime Prevention, Violence Prevention, Hot Spots Policing, General deterrence

Current Program Status: Not Active

Program Director:
Nola Joyce
Deputy Commissioner, Strategic Initiatives & Innovations
Philadelphia Police Department
One Franklin Square, Room 310
Philadelphia PA 19106
Phone: 215.686.3125