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.     

The Police Officer Perception Project (POPP): An experimental evaluation of factors that impact perceptions of the police

Objectives

To experimentally evaluate the effects of attire and patrol strategy esthetics on participants’ perceptions of police officers.

Methods

Using a rigorously controlled experimental methodology, I present participants (N = 307) with images of police officers in different attire (i.e., uniform and civilian) and patrol strategies (i.e., on a bicycle, on foot, and in a vehicle) and measure their perceptions of these officers as aggressive, approachable, friendly, respectful, and accountable.

Results

Participants express relatively positive perceptions of the police; however, their perceptions vary as a function of sociodemographics, attire, and patrol strategy. Police officers are generally perceived more favorably when presented in police uniform than when presented in civilian clothing. Police officers are also generally perceived more favorably when presented on a bicycle and/or on foot than when presented in a vehicle.

Conclusions

Merely observing police officers in different attire and patrol capacities produces substantial variation in perceptions of those officers. Given that most ‘police interaction’ occurs in relatively unceremonious settings without any exchange of formal dialogue between the public and the police (e.g., observing a police officer in passing), these findings are particularly fruitful for informing both research and practice. This is the first known study to use an experimental methodology to examine how esthetic factors of different patrol strategies can impact perceptions of the police.

     

Feelings of Safety In The Presence Of the Police,Security Guards,and Police Volunteers

Uniformed presence is commonly thought to create feelings of safety in people. However, do differently uniformed people contribute to an equal amount of safety and are there situation-dependent differences? The present study examined the association between various types of uniformed presence and people’s feelings of safety through a questionnaire among 352 respondents (18–86 years) (49.1 % women). The questionnaire contained pictures of situations perceived as relatively safe and unsafe with or without uniformed presence. The respondents estimated how safe they thought they would feel in these situations with no uniformed presence, two police officers, six police officers, a police vehicle, two security guards, or two police volunteers. Results showed that uniformed presence did not increase feelings of safety in a situation perceived as relatively safe, making patrol unnecessary. In situations perceived as relatively unsafe however, all types of uniformed presence increased feelings of safety. Foot patrolling police contributed to the greatest increase in feelings of safety. Security guards and police volunteers created similar amounts of feelings of safety making police volunteers a cost-effective alternative. All types of foot patrol were better than vehicle patrol, making non-police groups an alternative to vehicle patrol. Some situational, gender, and age differences were found.     

Aggressive Patrol: A Search for Side-effects

Recent interest in the possible deterrent effects of aggressive or proactive policing raises the issue of such strategies' consequences for individual liberties and police-community relations. This study examines the latter—specifically, the effects of four neighborhood-level measures of an aggressive patrol style on citizens' evaluations of police and citizens' propensities to report crimes. The results suggest that, for most citizens, aggressive patrol has almost no effect on either evaluations or reporting behavior. Surprisingly, one form of proactive patrol, the neighborhood rate of suspicion stops, seems to have a positive effect on the evaluations of police made by young black men.     

Just enough police presence: Reducing crime and disorderly behavior by optimizing patrol time in crime hot spots

Using observational data collected as part of a one-year preventive patrol study in Minneapolis, this investigation employs survival models to test hypotheses about the effects of specific instances of police patrol presence at high-crime locations on the time until the next occurrence of criminal or disorderly behavior at these locations. The results show that patrol stops must reach a threshold dosage of about 10 minutes in order to generate significantly longer survival times without disorder — i.e., greater residual deterrence — than that generated by driving through a hot spot. The optimal length for patrol stops appears to be 11 to 15 minutes. After that point, continued police presence brings diminishing returns. The theoretical and policy implications of these results are discussed.     

Public perceptions of female police officers on patrol

Women in policing have been the subject of considerable study for the past 20 years. While women perform as well as men in various patrol assignments and situations, they still face a significant amount of disapproval from the male police personnel population. Citizens, however, have shown a greater acceptance of women in this male-dominated occupation and a greater confidence in women’s abilities to effectively perform difficult patrol tasks. The purpose of the present research is to determine the perceptions that residents of two Kentucky counties have of female patrol officers and if those perceptions affirm previous findings. The socioeconomic foundations for those residents’ perceptions are also examined. The research instrument consisted of 17 closed-ended and matrix questions. Two hundred responses were obtained. The results of this study will indicate the public’s growing acceptance of women in this non-traditional gender role, which is a requisite development for the overall objective of attaining equality and equity for women in police work. Recommendations are presented for the purposes of explaining the inevitable changes in the gender makeup and purposes of police work and the need for police personnel and the public to accept those changes. Winner of 1995 Outstanding Undergraduate Paper Award, Southern Criminal Justice Association     

Aggressive Policing and the Deterrence of Crime

Recent analyses of the relationship between crime and an aggressive patrol strategy have led to no single conclusion concerning the deterrent power of aggressive policing. This research adds to that debate by exploring the effects of a variety of aggressive patrol tactics on several different crimes. The empirical analysis, based on cross-sectional data from sixty urban neighborhoods, indicates that there appears to be no stable complex of police actions that constitute an aggressive patrol strategy. However, one form of police action usually included under the rubric of aggressive patrol—suspicion stops—may indeed deter certain types of criminal activity.     

A multimethod approach to community evaluation of police performance

The aim of the present study is to examine the ability of police peers and supervisors to predict police street performance, as measured by citizen evaluations of the service received on recent police service calls. One question to be answered was whether there was any correlation between what a police supervisor, a police peer patrol officer, and a citizen percieved as “good” police performance. It was hypothesized that peer patrol officers would more accurately predict the quality of police street performance than would police supervisors. Results supported the hypothesis. An additional finding of the present study related to the feasibility of the evaluation of police street performance by citizen consumers.     

INVESTIGATING THE NORMATIVE ASPECTS OF PUBLIC POLICY

This article challenges the idea that political philosophy must be of peripheral concern in the study of public policy through an exploration of the concept of harm and the debate over aggressive police patrol. This exploration begins with a brief discussion of the ways the concept of harm figures in the justification and administration of police work. It proceeds through an exposition of differing ways the concept of harm can be defined, the normative overtones of these varying definitions, and some of their policy ramifications with regard to police work. Finally, the way conceptual variation figures in policy debate is explored in the context of the debate over aggressive police patrol—the policy of maximizing the surveillance and criminal interception aspects of police activity as a patrol strategy.     

DRIVING WHILE BLACK: BIAS PROCESSES AND RACIAL DISPARITY IN POLICE STOPS*

We estimate the degree of racial disparity in police vehicular stops separately for local and state police in North Carolina in the year 2000. We introduce four mechanisms that might produce racial disparities in police stops—racial profiling, race sensitive police deployment, cognitive bias and stereotyping, and prejudice. We then model the relative odds of police vehicle stops as a function of race, driving behavior, and other demographic statuses separately by police organization type, with controls for omitted variable bias at both the driver and spatial level. We find only weak evidence of racial disparity in stops by officers of the state highway patrol but stronger evidence in those made by local police officers.     

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.     

A comparison of Chinese and the U.S. police cadets’ occupational attitudes

While police attitudes and behaviors have been the subject of a large number of studies conducted since the 1960s, very few studies had assessed Chinese police officers’ work-related attitudes and compared them with those of the U.S. police cadets. Using survey data collected from 263 Chinese and American police cadets, the research empirically tested whether Chinese and American police cadet attitudes differed across four attitudinal dimensions: aggressive patrol, order maintenance, legal restrictions, and distrust of citizens. Bivariate and multivariate results showed that Chinese cadets displayed occupational outlooks that distinguished them from their American counterparts. Chinese cadets supported aggressive patrol and were more distrustful of citizens than their American counterparts. American cadets were more favorable of order maintenance activities and more accepting of legal restrictions compared with Chinese cadets. Implications for future research and policy are discussed.     

Police service aides: Paraprofessionals for police

Increased professionalization of U.S. police patrol forces has yielded not only higher salaries but, through heightened citizen expectations, greater pressures to provide both more crime-fighting and more call-for-service answering activities. Service calls in particular, requiring diversified skills, have added to patrol workloads. Coming at a time of severe budget constraints, alternatives must be identified and evaluated that focus police skills on police matters and provide for non-law-enforcement services in other ways. Recent experience on one promising alternative resource-police service aides-is summarized here. These paraprofessionals are unarmed but uniformed civilians in marked vehicles who perform non-crime-related activities traditionally assigned to sworn officers. Included is an analysis of their effectiveness in freeing time for sworn officers to pursue crime-fighting activities; their capacity to perform different duties; and their impact on and acceptance by the sworn officers and the community. As in other professions, the introduction of police paraprofessionals will have a major impact on urban services in general and on policing in particular.     

THE MANAGEMENT OF VIOLENCE BY POLICE PATROL OFFICERS*

This study examines the dynamics of potentially violent encounters between police and public. It is based on systematic observation of about 350 eight-hour tours of duty by patrol officers in three precincts of New York City during the summer of 1986. It compares the tactics and resulting outcomes found in encounters handled, respectively, by patrol officers believed by their peers to be especially skilled at minimizing violence and a cross section of all other patrol officers. Its major conclusions are (1) violence, even verbal aggression, is relatively rare in police work: (2) most conflict is dampened by the arrival of the police, leaving little scope for the use of defusing tactics: and (3) the behavior of officers judged by colleagues to be skilled in minimizing violence is measurably different from the behavior of “average” patrol officers, and in ways that suggest that colleagues may be good judges of on-street performance.     

Production appraisal of police patrol

Due to the increase in public expenditures for police protection during the past decade, it has become increasingly important to accurately measure patrol and service productivity. This article reviews conventional patrol and service practices and offers specific suggestions for improvement of patrol productivity.     

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.     

THE REASSURANCE FACTOR IN POLICE PATROL

In addition to its more obvious functions, police patrol also has the function of citizen reassurance-providing feelings of safety that a citizen experiences when he knows that a police officer or patrol car is nearby. Since this function is highly related to both visibility and awareness, it is svggested that in locations of both cognitive centrality and high density, fixed posts be established that would both serve the reassurance function and provide another communication link between the police and the public. Recent studies by Milgram. Sommer, Hall, and Lynch have all contributed to our understanding of what Milgram calls “the congnitive map of the city,” and this concept can be utilized in the pursuit of safety.     

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.     

Police supervision on the street: An analysis of supervisor/officer interaction during the shift

This article examines a major assumption of street supervisors in police agencies—that control of police officer behavior is dependent on strict hierarchical organization. The intellectual roots of this assumption are examined, and an emerging perspective developed from direct observation of patrol operations is presented. The research questions are addresses with data that were collected from observations of patrol activities in 60 residential neighborhoods in 24 agencies. The analysis, which is referenced to officers' shifts of duty, shows that the effect of supervision is in the direction posited by the authors of traditional police administration texts, but the magnitude of the effect is not overly strong. The findings are used to inform the evaluation of a common policy option directed at improving officer performance through supervision.     

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.