Does police patrol in large areas prevent crime? Revisiting the Kansas City Preventive Patrol Experiment

Research Summary

The Kansas City Preventive Patrol Experiment (KCPPE) was seen by its developers to have produced “consistent evidence of the lack of effects of any consequence on crime,” a conclusion that was to have a strong impact on assumptions about police patrol for almost half a century. We identified the original official crime data from the KCPPE, and reanalyzed outcomes focusing on a comparison of the “proactive” versus “control” beats (“reactive beats” were criticized because of violations of treatment integrity); examining broad categories of crime (to increase statistical power); and using count regression models. Our findings are not unequivocal, but point to modest impacts of police patrol on crime in police beats.

Policy Implications

Our findings suggest that lessons drawn for half a century from the KCPPE need to be revisited. The KCPPE does not show that police patrol in large areas has no influence on crime, and this finding is consistent with several more recent studies. At the same time, we note that the effects of patrol in the KCPPE using our analysis strategy, and those found in other studies of preventive patrol in larger areas, are about half that found in hot spots policing studies. This suggests that police agencies ideally should invest in focused hot spots policing initiatives. However, absent an ability to manage such initiatives, or the crime analysis capabilities to identify crime hot spots routinely, simpler preventive patrol schemes to utilize uncommitted patrol time can be seen as potentially effective in preventing crime.     

What happened to patrol operations in Kansas city? A review of the Kansas city preventive patrol experiment

This paper reviews important aspects of the design, execution, and evaluation of the Kansas City Preventive Patrol Experiment. The focus is on the operational behavior of the patrol force during the experiment and not on before-and-after crime statistics. Where appropriate, simple probabilistic models are employed to estimate frequencies of preventive patrols and response times in each of the experimental areas. These models, together with experimental data, demonstrate that (1) typical patrol intensities in Kansas City are not large enough to encompass the range of patrol intensities experienced in other cities, and (2) patrol visibility in the depleted areas (the reactive beats) due to responding calls for service is relatively quite large, perhaps even equalling the pre-experimental levels during high workload periods. Such models also demonstrate that travel distances into the reactive beats should not be markedly increased, as the researchers had expected.Based on models and experimental data, the analysis indicates that the particular experimental design used in Kansas City resulted in a significant continued patrol presence in the depleted areas, with little increase in travel times in those areas. This suggests two policy conclusions: (1) great caution should be used in attempting to induce the general value of a visible patrol presence from the results of the Kansas City Preventive Patrol Experiment; (2) patrol administrators in other cities could, on a day-by-day basis if need be, remove conventional patrol coverage from certain beats and markedly increase manning in others nearby without incurring significant degradations in service (either actual or perceived) in the depleted areas. This second possibility facilitates the implementation of crime-directed patrol efforts.     

Applications of crime seriousness information in police departments

This article describes the use of crime seriousness information in police operations. It is based on a project at the St. Louis Metropolitan Police Department in which eight weeks of crime information were coded using the Sellin-Wolfgang seriousness scale. Statistics were then derived which quantified the seriousness of the various categories of crimes. Several applications were investigated based on the crime seriousness data. These included: (1) case assignment to detectives, (2) allocation of patrol personnel, and (3) determination of the size and location of patrol beats. Areas for future research are presented involving the use of crime seriousness data.     

DOES WHAT POLICE DO AT HOT SPOTS MATTER? THE PHILADELPHIA POLICING TACTICS EXPERIMENT*

Policing tactics that are proactive, focused on small places or groups of people in small places, and tailor specific solutions to problems using careful analysis of local conditions seem to be effective at reducing violent crime. But which tactics are most effective when applied at hot spots remains unknown. This article documents the design and implementation of a randomized controlled field experiment to test three policing tactics applied to small, high‐crime places: 1) foot patrol, 2) problem‐oriented policing, and 3) offender‐focused policing. A total of 81 experimental places were identified from the highest violent crime areas in Philadelphia (27 areas were judged amenable to each policing tactic). Within each group of 27 areas, 20 places were randomly assigned to receive treatment and 7 places acted as controls. Offender‐focused sites experienced a 42 percent reduction in all violent crime and a 50 percent reduction in violent felonies compared with their control places. Problem‐oriented policing and foot patrol did not significantly reduce violent crime or violent felonies. Potential explanations of these findings are discussed in the contexts of dosage, implementation, and hot spot stability over time.     

Traffic Stops in the Pacific Northwest

ABSTRACT

This study examines the distribution of police traffic warning citations in a large northwestern city. Warning tickets were instituted to document the exercise of police discretion in the disposition of traffic stops. The paper tests three competing hypotheses about how these citations are distributed: law enforcement, traffic enforcement, and group threat. The findings show greater support for the group threat explanation. African Americans were disproportionately ticketed in the more affluent areas of the city with a higher per capita income and a higher percentage of home ownership. The data also demonstrated that traffic officers were more active than patrol officers in predominately white beats while patrol officers concentrated more on African American and Asian areas of the city.     

Spatial Patterns of Robbery at Tourism Sites: A Case Study of the Vieux Carré in New Orleans

This paper looks at the connection between spatial patterns of robbery within the framework of routine activities theory. This theoretical perspective sees robbery (and other crimes) as occurring when three factors converge: suitable targets, motivated offenders and guardianship. The Eighth and part of the First Police Districts of New Orleans become target rich environments during periods of time when large numbers of tourists and conventioneers are in the city. The city certainly has the neighborhoods of highly concentrated poverty and disorganization that tend to be criminogenic and produce motivated offenders. The spatial distribution of robbery is hypothesized to be a function of the presence or absence of guardianship. In order to test this hypothesis two types of data are examined: robberies (simple, armed, both successful and attempted) that occurred during the convention and tourism season and patterns of deployment and patrol in these areas. Preliminary results indicate that simple tourist/conventioneer robbery victimizations tend to be concentrated within tourist attraction areas while aggravated tourist/conventioneer robbery is concentrated in places that are primarily residential and where there are no attractions and no concentrated police presence. This is also an area of ingress and egress for people from perimeter neighborhoods of highly concentrated poverty and disorganization.     

Urban crime trends and patterns in Ghana: The case of Accra

The study examined the broad crime trends and patterns, and the conditions under which crimes flourish, the crime incidence rates per 1,000 of population, and crime among the four police divisions of Accra, Ghana. Where crimes clustered the most and the times some crimes were committed were examined using the official police data. The study suggests that crime in Accra has been accentuated by rigid centralization of government bureaucracy, the nature of Ghana's economy, routine activities, lifestyles, and opportunities fostered by social change. Overall, the Accra Central Police Division recorded the highest volume of crimes, followed by the Nima, Kaneshie, and Kpeshie Divisions. The highest property offenses were recorded within twelve miles of the city center—the area most congested and heavily concentrated with socio-economic and routine activities. Calls for the adoption of situational crime prevention methods and strategies to reduce the incidence of crime in Accra have been made.     

Foot Patrol in Violent Crime Hot Spots: The Longitudinal Impact of Deterrence and Posttreatment Effects of Displacement

This study revisited the Philadelphia Foot Patrol Experiment and explored the longitudinal deterrent effects of foot patrol in violent crime hot spots using Sherman's (1990) concepts of initial and residual deterrence decay as a theoretical framework. It also explored whether the displacement uncovered during the initial evaluation decayed after the experiment ended. Multilevel growth curve models revealed that beats staffed for 22 weeks had a decaying deterrent effect during the course of the experiment, whereas those staffed for 12 weeks did not. None of the beats had residual deterrence effects relative to the control areas. The displacement uncovered had decayed during the 3 months after the experiment, and it is theoretically plausible that previously displaced offenders returned to the original target areas causing inverse displacement. These results are discussed in the context of Durlauf and Nagin's (2011) recent proposal that prison sentences should be shortened, mandatory minimum statutes repealed, and the cost savings generated by these policy changes shifted into policing budgets to convey more effectively the certainty of detection. It is concluded that if Durlauf and Nagin's proposal is to succeed, then more holistic policing strategies would likely be necessary. Foot patrol as a specific policing tactic seems to fit nicely into a variety of policing paradigms, and suggestions for incorporating them to move beyond strictly enforcement‐based responses are presented.     

Testing hot-spots police patrols against no-treatment controls: Temporal and spatial deterrence effects in the London Underground experiment

Our understanding of causality and effect size in randomized field experiments is challenged by variations in levels of baseline treatment dosage in control groups across experiments testing similar treatments. The clearest design is to compare treated cases with no-treatment controls in a sample that lacks any prior treatment at baseline. We applied that strategy in a randomized test of hot-spots police patrols on the previously never-patrolled, track-level platforms of the London Underground (LU). In a pretest–posttest, control-group design, we randomly assigned 57 of the LU's 115 highest crime platforms to receive foot patrol by officers in 15-minute doses, 4 times per day, during 8-hour shifts on 4 days a week for 6 months. The effect of 23,272 police arrivals at the treatment hot spots over 26 weeks was to reduce public calls for service by 21 percent on treated platforms relative to controls, primarily when police were absent (97 percent of the measured effect). This effect was six times larger than the mean standardized effect size found in the leading systematic review. This finding provides a benchmark against the baseline counterfactual of no patrol in hot spots, with strong evidence of residual deterrence and no evidence of local displacement.     

Police Perceptions of Computer Crimes in Two Southeastern Cities: An Examination from the Viewpoint of Patrol Officers

Although scholars and law enforcement administrators have provided input on how local law enforcement is responding to various forms of computer crime and how officers perceive of it, patrol officers have been rarely surveyed to understand their perceptions of computer crime. Examining officer perceptions is vital considering that patrol officers are being asked to be more effective first responders to digital forensic crime scenes as a critical step in combating computer crimes at the local level. This study therefore addressed this gap by surveying patrol officers in two southeastern cities regarding their perceptions of computer crime, specifically regarding its uniqueness, offenders and targets, and seriousness and frequency in comparison to traditional forms of crime. Results indicated that many officers do not have strong opinions on several aspects of computer crime. However, they perceive it to be a serious problem and consider some computer crimes to be as serious as traditional forms of crime.     

THE PHILADELPHIA FOOT PATROL EXPERIMENT: A RANDOMIZED CONTROLLED TRIAL OF POLICE PATROL EFFECTIVENESS IN VIOLENT CRIME HOTSPOTS*

Originating with the Newark, NJ, foot patrol experiment, research has found police foot patrols improve community perception of the police and reduce fear of crime, but they are generally unable to reduce the incidence of crime. Previous tests of foot patrol have, however, suffered from statistical and measurement issues and have not fully explored the potential dynamics of deterrence within microspatial settings. In this article, we report on the efforts of more than 200 foot patrol officers during the summer of 2009 in Philadelphia. Geographic information systems (GIS) analysis was the basis for a randomized controlled trial of police effectiveness across 60 violent crime hotspots. The results identified a significant reduction in the level of treatment area violent crime after 12 weeks. A linear regression model with separate slopes fitted for treatment and control groups clarified the relationship even more. Even after accounting for natural regression to the mean, target areas in the top 40 percent on pretreatment violent crime counts had significantly less violent crime during the operational period. Target areas outperformed the control sites by 23 percent, resulting in a total net effect (once displacement was considered) of 53 violent crimes prevented. The results suggest that targeted foot patrols in violent crime hotspots can significantly reduce violent crime levels as long as a threshold level of violence exists initially. The findings contribute to a growing body of evidence on the contribution of hotspots and place‐based policing to the reduction of crime, and especially violent crime, which is a significant public health threat in the United States. We suggest that intensive foot patrol efforts in violent hotspots may achieve deterrence at a microspatial level, primarily by increasing the certainty of disruption, apprehension, and arrest. The theoretical and practical implications for violence reduction are discussed.     

Managing Police Patrol Time: The Role of Supervisor Directives

Contemporary police practice advocates the importance of proactive policing activities. Proactive policing reforms emphasize self‐initiated tasks during unassigned patrol time and directed activities based on supervisor review of crime analysis and problem identification. Our study analyzes data from systematic social observations of police patrol officers to examine how officers spent their discretionary time. We find that, on average, over three quarters of a patrol officers’ shift is unassigned. During this time, officers primarily self‐initiate routine patrol, or back up other officers on calls to which they were not dispatched. Just 6 percent of unassigned time activities are directed by supervising officers, dispatchers, other officers or citizens. Moreover, directives provided by supervisors are vague, general in form, and do not operationalize problem‐oriented policing, community‐oriented policing, or proactive policing strategies. We conclude that first, a very significant proportion of patrol officer time is spent uncommitted that could be better utilized doing proactive, problem‐oriented policing activities, and second, supervisors need to provide patrol officers with much more detailed directives, based on sound crime analysis, to help capitalize on the under‐utilization of patrol officer time.     

REDUCING FIREARMS VIOLENCE THROUGH DIRECTED POLICE PATROL*

Research Summary: This evaluation of a directed police patrol project utilizes a pre-post quasi-experimental design with a non-equivalent control group as well as an interrupted time series analysis. The results suggest that directed patrol had an impact on firearms crime in one of the target areas but not the other. Policy Implications: The results suggest that a specific deterrence strategy whereby the police utilize directed patrol to focus on suspicious activities and locations reduced violent gun crime. In contrast, a general deterrence strategy focused on maximizing vehicle stops did not have an apparent effect.     

The urban anti-crime patrol phenomenon: A case study of a student effort

During the past decade Americans have engraved property, joined block watch organizations, and organized anti-crime patrols, often because they believed crime was out of control. In general such efforts tend to be short-lived, progressing from initial enthusiasm to a relatively brief period of operation and eventual death. What are the key factors in this natural history of citizen anti-crime actions? Drawing on interviews of patrol leaders and members, participant observation, an analysis of campus newspaper stories, and responses to open-ended survey items, this paper tries to answer this question by examining a student patrol at Drake University. The research reveals that the campus crime “problem” was largely the product of student newspaper emphasis, the patrol was able to function because the university provided the necessary resources, and participants joined for a variety of motives. The patrol eventually declined, however, because the student newspaper no longer emphasized the crime problem; student participation decreased because of the monotony associated with surveillance and the existence of organizational problems, especially the lack of strong leadership.     

Community reponse to crime: Two middle-class anti-crime patrols

This paper examines two middle-class citizen patrols in the light of previous studies of patrols in lower- and working-class communities situated in very large urban areas. Consistent with previous research, our data show that patrol participation is related to the belief that citizens should play a role in crime prevention, to a slightly lower fear of crime, and to general social involvement. Contrary to previous findings, length of residence, age, and victimization were not found to be related to patrol participation. Patrol participants were more likely to believe that citizens have some responsibility for crime prevention and to have engaged in more anti-crime activities than nonparticipants. Residents strongly rejected the vigilante analogy and appeared, instead, to define patrol participation as a manifestation of good citizenship.     

The influence of job assignment on community engagement: bicycle patrol and community-oriented policing

The purpose of this study is to compare a specialized community-oriented policing (COP) unit to a reactive unit on officer perceptions of public contact and officer perceptions of job performance. We also compare bicycle patrol officers to motor vehicle patrol officers within these units. Using a static group comparison design, questionnaires were distributed to officers within the Toronto Police Service (n = 178). Bicycle patrol is associated with more contacts with the public and higher rates of proactive policing when compared to motor vehicle patrol and bicycle officers are more likely to rate higher on several measures of crime control. Officers with a COP mandate engage with the public for a wider variety of reasons compared to those with a reactive mandate, and are more likely to rate higher on perceptions of performing job duties in a procedurally just manner. This study demonstrates the value of a specialized COP unit that includes bicycle patrol in achieving tenets of COP. It contributes to the literature on COP and the use of bicycle patrol in law enforcement by presenting the perspective of the police officer.     

The efficacy of foot patrol in violent places

Objectives

This study examines the effectiveness of foot patrol in violent micro-places. A large urban police department deployed foot patrol in micro-places (hot spots) for a period of 90 days for two shifts each day. Our objective is to determine whether this activity impacted violent crime in these hot spots and whether spatial displacement of crime occurred.

Methods

Eight eligible foot beat locations were set by examining crime rates for previous years in order to identify micro-places of high criminal activity. We employed a quasi-experimental design comparing the four treatment to the four control areas, estimating panel-specific autoregressive models for 30 weeks prior to and 40 weeks after the treatment.

Results

Time series models revealed statistically significant reductions in violent crime in the micro-places receiving foot patrol treatment, while no such reductions were observed in the control areas. The deterrent effect, however, was short and dissipated quickly. Control areas did not experience any crime prevention benefit during this time period. No evidence of crime displacement to spatially contiguous areas was detected.

Conclusions

This contributes to the growing body of knowledge that focused police strategies within hot spots impact violent crime. Specifically, the implementation of foot patrol in high crime hot spots led to measurable reductions in aggravated assaults and robberies, without displacing crime to contiguous areas.

     

Identifying changes in spatial patterns from police interventions: the importance of multiple methods of analysis

The policing initiative of foot patrol was implemented to reduce crime and disorder as well as benefit the relationship between the community and the police in the community of Lower Lonsdale, North Vancouver, British Columbia. In this paper, police incident data are analyzed to evaluate the impact of police foot patrol on the hot spots of crime in this community. Specifically, two spatial analysis techniques (kernel density estimation and local Moran’s I) are used to show how the nuances of changes in spatial crime patterns can emerge when multiple methods of analysis are used.     

A randomized controlled trial of different policing strategies at hot spots of violent crime

Focusing police efforts on “hot spots” has gained acceptance among researchers and practitioners. However, little rigorous evidence exists on the comparative effectiveness of different hot spots strategies. To address this gap, we randomly assigned 83 hot spots of violence in Jacksonville, Florida, to receive either a problem-oriented policing (POP) strategy, directed-saturation patrol, or a control condition for 90 days. We then examined crime in these areas during the intervention period and a 90-day post-intervention period. In sum, the use of POP was associated with a 33% reduction in “street violence” during the 90 days following the intervention. While not statistically significant, we also observed that POP was associated with other non-trivial reductions in violence and property crime during the post-intervention period. In contrast, we did not detect statistically significant crime reductions for the directed-saturation patrol group, though there were non-significant declines in crime in these areas during the intervention period. Tests for displacement or a diffusion of benefits provided indications that violence was displaced to areas near the POP locations, though some patterns in the data suggest this may have been due to the effects of POP on crime reporting by citizens in nearby areas. We conclude by discussing the study’s limitations and the implications of the findings for efforts to refine hot spots policing.     

A randomized test of initial and residual deterrence from directed patrols and use of license plate readers at crime hot spots

Objectives

To test the effects of short-term police patrol operations using license plate readers (LPRs) on crime and disorder at crime hot spots in Mesa, Arizona.

Methods

The study employed a randomized experimental design. For 15 successive 2-week periods, a four-officer squad conducted short daily operations to detect stolen and other vehicles of interest at randomly selected hot spot road segments at varying times of day. Based on random assignment, the unit operated with LPRs on some routes and conducted extensive manual checks of license plates on others. Using random effects panel models, we examined the impact of these operations on violent, property, drug, disorder, and auto theft offenses as measured by calls for service.

Results

Compared to control conditions with standard patrol strategies, the LPR locations had reductions in calls for drug offenses that lasted for at least several weeks beyond the intervention, while the non-LPR, manual check locations exhibited briefer reductions in calls regarding person offenses and auto theft. There were also indications of crime displacement associated with some offenses, particularly drug offenses.

Conclusions

The findings suggest that use of LPRs can reduce certain types of offenses at hot spots and that rotation of short-term LPR operations across hot spots may be an effective way for police agencies to employ small numbers of LPR devices. More generally, the results also provide some support for Sherman’s (1990) crackdown theory, which suggests that police can improve their effectiveness in preventing crime through frequent rotation of short-term crackdowns across targets, as it applies to hot spot policing.