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Philadelphia Foot Patrol Experiment

The Philadelphia Foot Patrol Experiment was a major research collaboration between the Philadelphia Police Department and researchers in the Department of Criminal Justice involving over 200 police officers on foot beats around some of the city’s most violent corners.

Since the 1980s, it had long been the opinion of many police and criminology researchers that police foot patrols improve community perception of the police and reduce fear of crime, but they don’t prevent actual crime. Results from the Philadelphia Foot Patrol Experiment suggested a more positive view of intelligence-led targeting of foot patrol officers to violent crime hot spots.

Research design

On the invitation of the Philadelphia Police Department, police and academic researchers worked together to plan the Philadelphia Foot Patrol Experiment as a randomized and controlled field experiment. With the resources to patrol 60 locations, researchers identified the highest violent crime corners in the city, using data from 2006 to 2008. Police commanders then designed 120 foot patrol areas around these corners, and stratified randomization was used to assign pairs of foot patrols with similar crime rates as either a control or a target area.

Officers patrolled in pairs with two pairs assigned to each foot patrol. They worked from Tuesday to Saturday in two shifts (10am to 6pm, 6pm to 2am) during the summer of 2009. After three months, relative to the comparison areas, violent crime decreased 23%. Official records of police activities during the intervention period reveal the following in the target areas: Drug‐related detections increased 15%, pedestrian stops increased 64%, vehicle stops increased 7%, and arrests increased 13%. Even with some crime displacement to nearby locations, analysis indicated that the foot patrols prevented 53 violent crimes during the summer.

With the help of friends at the Philadelphia Police Department, I also created a short six-minute video outlining the research shown here:

This project won the 2010 Excellence in Law Enforcement Research Award from the International Association of Chiefs of Police and the 2013 Outstanding Experimental Field Trial Award from the American Society of Criminology’s Division of Experimental Criminology.

The experimental results were reported in the journal Criminology. The full citation is: Ratcliffe, J. H., Taniguchi, T., Groff, E.R., & Wood, J. (2011) The Philadelphia Foot Patrol Experiment: A randomized controlled trial of police patrol effectiveness in violent crime hotspots. Criminology, 49(3), 795-831. It is article number 43 here. 


A three-page research summary pdf is also available and is probably more accessible that the Criminology paper.

There is a 12 minute audio summary of the experiment available, including interviews with Larry Sherman and David Weisburd, as well as with Philadelphia Police Department officers 

Follow-up research and other findings

Was there a long-term impact of foot patrol?

Subsequent research by our team examined the long-term impacts of the Philadelphia Foot Patrol Experiment to determine what happened after the experiment was over. Results showed that beats that were in place beyond three months had diminishing effects during the experiment, an effect not seen with the shorter term beats. Foot patrol beats returned to their pre-experiment crime levels once the foot patrol experiment was concluded and the foot patrols were largely withdrawn. There was no evidence that the benefits from the Philadelphia Foot Patrol Experiment lasted beyond the time when the officers were assigned to the beats. These findings were published in an article in Criminology. It is article number 49 here.

Did the presence of foot patrol change the way car patrols were used?

The question of how foot patrol affected the car patrol officers in which the foot beats were embedded was also examined by the team. Official data describing the activities of foot and car patrol officers was analyzed. We found noticeable differences in the activities of the two types of patrol. Foot patrol was more likely to conduct pedestrian stops and deal with disorder and drug offenses while car patrol handled the vast majority of reported crime incidents and calls from the public. As a result, police managers and researchers should consider the impact of new strategies on the dominant patrol style. Co-production of community safety among officers assigned to different patrol styles is an under-researched area with potential for improving the success of crime reduction efforts through better internal coordination of police resources. These findings were published in an article in Policing: An International Journal of Police Strategies and Management. It is article number 48 here.

What was the experience of foot patrol officers?

During the experiment we conducted field observations alongside the foot patrol officers. The observations were designed to capture officers’ perceptions of and experiences with the foot patrol function. Officers developed extensive local knowledge of their beat areas, and were what we call ‘reflective agents’ with varying styles and approaches to their foot patrol role. They had to negotiate the tension between what they perceived to be ‘real police work’ (arresting offenders) and the ‘reassurance’ function of foot patrol. They exerted spatial control of their beats through a repertoire of techniques which depended in part on officer style. We also learned that in some ways, the experimental nature of the intervention clashed with the common sense judgment of officers, including the need to adapt policing practices to changing criminal behavior. This research reinforces the need to integrate line officer knowledge in the design of place-based interventions. These findings can be found in an article in Policing and Society. It is article number 51 here.

Did the officers remain in their assigned beats?

Not entirely. During focus groups conducted with foot patrol officers after the experiment, we gave officers maps of their beats and asked where they actually patrolled. In general, the areas they actually patrolled were about 0.13 square miles greater than the originally assigned patrol zones. Officers left their assignments for a number of reasons, including because they perceived that offenders had adapted to their patrol areas and moved to nearby locations, because they felt that areas just out side their beat should have been included in the area because specific locations caused community problems, and sometimes to add some variety when they became bored with patrolling the same area every day. More details of these findings can be found in our article in the Journal of Research in Crime and Delinquency. It is article number 53 here.

What public health challenges did officers face on their beats?

While the officers worked to establish rules and exercise some control over the areas they policed, they spent considerable time dealing with populations of people on the verges of society. On a daily basis, foot patrol officers assigned to small areas come face-to-face with not only traditional issues of crime, but also addition, mental illness, and homelessness. They struggled to see addicted drug users as vulnerable people at higher risks of morbidity and mortality; however, officers were more inclined to view people affected by mental illness as more vulnerable than threatening. They also had to deal with ‘microplaces of harm’ such as abandoned houses used for prostitution and drug use. In the end, officers, and foot patrol officers in particular, are ‘public health interventionists’. See our article in Police Practice and Research. It is article number 54 here.

Related research

Please also take a look at:

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