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.     

Hot spots policing and crime prevention: A systematic review of randomized controlled trials

Crime scholars and practitioners have argued that police actions should be focused on high-risk crime places rather than spread thinly across the urban landscape. This review examines five randomized controlled trials of the effects of concentrating police enforcement efforts on crime hot spots. The findings of these evaluations suggest that focused police actions can prevent crime and disorder in crime hot spots. A meta-analysis of the effect sizes from the five experiments reveals a statistically significant mean effect size for hot spots policing interventions; this suggests overall reductions in citizen calls for service in the treatment hot spots relative to the control hot spots. These studies also suggest that focused police actions at specific locations do not necessarily result in crime displacement. Although these evaluations reveal that these programs work in preventing crime, additional research is needed to unravel other important policy-relevant issues such as community reaction to focused police enforcement efforts.     

CAN HOT SPOTS POLICING REDUCE CRIME IN URBAN AREAS? AN AGENT‐BASED SIMULATION*

Over the past two decades, there has been a growing consensus among researchers that hot spots policing is an effective strategy to prevent crime. Although strong evidence exists that hot spots policing will reduce crime at hot spots without immediate spatial displacement, we know little about its possible jurisdictional or large‐area impacts. We cannot isolate such effects in previous experiments because they (appropriately) compare treatment and control hot spots within large urban communities, thus, confounding estimates of area‐wide impacts. An agent‐based model is used to estimate area‐wide impacts of hot spots policing on street robbery. We test two implementations of hot spots policing (representing different levels of resource allocation) in a simulated borough of a city, and we compare them with two control conditions, one model with constant random patrol and another with no police officers. Our models estimate the short‐ and long‐term impacts on large‐area robbery levels of these different schemes of policing resources. These experiments reveal statistically significant effects for hot spots policing beyond both a random patrol model and a landscape without police. These simulations suggest that wider application of hot spots policing can have significant impacts on overall levels of crime in urban areas.     

The Impact of Hot Spots Policing on Collective Efficacy: Findings from a Randomized Field Trial

In disadvantaged neighborhoods, prior research has found reduced social cohesion and less willingness among residents to address disruptive behaviors and violations of social norms. This deficiency is commonly associated with higher levels of disorder and crime. Therefore, recent scholarship has begun to consider whether police can help foster collective efficacy, especially in places struggling with serious crime problems. Early results are somewhat mixed. Yet the cooperation hypothesis asserts that when neighborhood residents see police as a more viable and reliable resource, residents will be emboldened to exert informal social control to address problems. Over the last two decades, hot spots policing has been recognized as an effective method to reduce crime. At the same time, there have been few rigorous studies of whether this approach impacts collective efficacy at hot spots. To investigate this question, we conducted an experiment in 71 crime hot spots, comparing a collaborative problem solving versus a directed patrol (police presence) approach versus standard policing practices. Over time, a substantial increase in police presence did appear to promote modest improvements in collective efficacy. We attribute this finding to the cooperation hypothesis.     

Hot Spots of Crime and Place‐Based Prevention

The August Vollmer Award Address is intended to focus on contributions to justice and on the recipient's research and policy experiences. This contribution begins with the recipient recapping his personal journey to recognizing hot spots of crime and their importance for prevention. He then goes on to summarize the “law of crime concentration” and its importance for the logic model underlying this approach. He describes the seminal Minneapolis Hot Spots Patrol Experiment and the subsequent evaluation research in hot‐spots policing and place‐based prevention more generally that led to its broad acceptance as an effective crime prevention strategy. Finally, the author turns to key unanswered questions in place‐based prevention, focusing on police legitimacy, identifying jurisdictional effects, and emphasizing the importance of harnessing informal social controls.     

The Extent and Correlates of Public Support for Deterrence Reforms and Hot Spots Policing

As one approach to prison downsizing and criminal justice reform, scholars recommend altering the nature of policing by reallocating resources toward policing and increasing sentinel patrols and hot spots interventions. Public attitudes toward these reforms are unknown. In the current police crisis, shifting policies in ways disfavored by the public can impact police‐community relations, especially among those disproportionately affected. The current study uses survey data from a nationally representative sample of Americans to evaluate whether the public is receptive to the suggested reforms. Our results indicate that the majority of the general public believes policing is more cost‐effective than incarceration and supports a focus on sentinel patrols and crime hot spots, although there is less support for hot spots policing among blacks, Hispanics, and lower income individuals. The hot spots policing strategy most preferred is situational prevention, and the least supported is aggressive order‐maintenance policing.     

How Much Time Should the Police Spend at Crime Hot Spots? Answers from a Police Agency Directed Randomized Field Trial in Sacramento,California

Hot spots policing has been shown to be an effective strategy for reducing crime across a number of rigorous evaluations, but despite this strong body of research, there still exist gaps in our knowledge of how officers can best respond to hot spots. We report on a randomized experiment in Sacramento, California that begins to address these gaps by testing the recommendation from prior research that police officers randomly rotate between hot spots, spending about 15?min patrolling in each. Our results suggest significant overall declines in both calls for service and crime incidents in the treatment hot spots relative to the controls. Additionally, the study was carried out primarily by the Sacramento Police Department without any outside funding. In an era of limited economic resources for policing, this experiment suggests a model by which police agencies can take ownership of science and oversee the implementation and evaluation of evidence-based interventions.     

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.     

PROBLEM-ORIENTED POLICING IN VIOLENT CRIME PLACES: A RANDOMIZED CONTROLLED EXPERIMENT*

Over the past decade, problem-oriented policing has become a central strategy for policing. In a number of studies, problem-oriented policing has been found to be effective in reducing crime and disorder. However, very little is known about the value of problem-oriented interventions in controlling violent street crime. The National Academy of Sciences' Panel on the Understanding and Control of Violent Behavior suggests that sustained research on problem-oriented policing initiatives that modify places, routine activities, and situations that promote violence could contribute much to the understanding and control of violence. This study evaluates the effects of problem-oriented policing interventions on urban violent crime problems in Jersey City, New Jersey. Twenty-four high-activity, violent crime places were matched into 12 pairs and one member of each pair was allocated to treatment conditions in a randomized block field experiment. The results of the impact evaluation support the growing body of research that asserts focused police efforts can reduce crime and disorder at problem places without causing crime problems to displace to surrounding areas.     

The irony of broken windows policing: A micro-place study of the relationship between disorder, focused police crackdowns and fear of crime

In their seminal “Broken Windows” article in Atlantic Monthly, J. Q. Wilson and G. L. Kelling (1982) suggested that police could more effectively fight crime by targeting minor offenses. They hypothesized that untended disorder increases fear of crime in a community, starting a chain of events that eventually leads to heightened levels of crime. By targeting disorder, police can thus circumvent this cycle of neighborhood decline (Skogan, 1990). This study aimed to improve knowledge of the relationship between disorder and fear of crime in the context of the broken windows hypothesis by using a micro-place level research design involving a police crackdown on disorder and minor crime at hot spots. The results of the current study suggest that perceived social disorder and observed levels of physical disorder have a strong impact on fear of crime. This confirms the relationship between disorder and fear hypothesized by the broken windows literature, and implies that police may be able to reduce fear of crime by reducing disorder. It was also found, however, that the police intervention itself significantly increased the probability of feeling unsafe. Accordingly, any fear reduction benefits gained by reducing disorder may be offset by the fact that the policing strategies employed simultaneously increase fear of crime. These findings suggest the importance of a careful focus on “how” broken windows policing programs are implemented. Such programs must be geared not only to reduce disorder, but also to prevent increases in citizen fear that accompany crackdowns and other intensive enforcement efforts associated with broken windows policing.     

THE EFFECTS OF DIRECTED PATROL AND SELF‐INITIATED ENFORCEMENT ON FIREARM VIOLENCE: A RANDOMIZED CONTROLLED STUDY OF HOT SPOT POLICING

Targeted policing has proven effective in reducing serious crime in areas where it is highly concentrated, but the enforcement mechanisms responsible for the success of so‐called hot spots strategies remain poorly understood. This study evaluates the effects of a 9‐month randomized controlled hot spots field experiment on firearm assaults and robberies in St. Louis, Missouri. Thirty‐two firearm violence hot spots were randomly allocated to two treatment conditions and a control condition. Directed patrols were increased in both treatment conditions, whereas the experimental protocol limited other enforcement activity in one of the treatment conditions and increased it in the other. The results from difference‐in‐difference regression analyses indicate that the intervention substantially reduced the incidence of nondomestic firearm assaults, with no evident crime displacement to surrounding areas, to times when the intervention was not active, or to nonfirearm assaults. By contrast, we find no effects of the intervention on firearm robberies. Less definitive results suggest that the certainty of arrests and occupied vehicle checks account for the treatment effects on nondomestic firearm assaults.     

Could Innovations in Policing have Contributed to the New York City Crime Drop even in a Period of Declining Police Strength?: The Case of Stop,Question and Frisk as a Hot Spots Policing Strategy

Available data make it impossible to reach strong conclusions about the role of policing in the New York crime decline. Instead, we examine whether innovations implemented in New York fit with what is known about effective policing strategies. Our main analysis focuses on how the New York City Police Department (NYPD) could have continued to contribute to the crime drop over the last decade when the number of police declined significantly. We examine geographic data on crime and stop, question and frisks (SQFs) to show that SQFs are concentrated at crime hot spots. We also show that the NYPD increased these specific hot spots policing strategies despite declining numbers. In our discussion, we speculate on whether this “doing more with less” could be an explanation for the continued crime drop in New York, noting the limitations of drawing conclusions from existing data. We also raise concerns about possible backfire effects of SQF hot spots approaches.     

An assessment of the impact of quality-of-life policing on crime and disorder

In this paper we examine the impact of quality-of-life policing on crime and disorder. Specifically, we examine a quality-of-life initiative conducted by the Chandler, Arizona Police Department, which was grounded in an operational strategy of policing social and physical disorder. Using data on calls for service, we employ an interrupted time-series analysis to examine the effect of the intervention on 10 offense categories within the overall target area and within four zones that constitute the target area. The findings suggest that the quality-of-life initiative exerted the strongest effect on two categories of crime and disorder: public morals and physical disorder. Diffusion of benefit and displacement effects were also observed in nearby areas. We discuss the implications of the findings for policy makers and researchers.     

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.     

Drive-away policing and situational crime prevention in China: an analysis of motorcycle ban (jinmo) policy in Guangzhou

Using the example of motorcycle ban policy in Guangzhou, the capital of Guangdong province, this article examines how situational crime prevention strategies are used in contemporary urban China. The article argues that although a motorcycle ban policy may reduce motorcycle snatch theft (feiche qiangduo) in Guangzhou, it inevitably caused a problem of displacement. However, some types of displacement are desirable for local government. An argument about drive-away policing is proposed in this article to understand policing styles in contemporary China. In addition, the article argues that motorcycle ban, as a strategy to prevent snatch theft and robbery, is also a strategy to deal with the crisis in police legitimacy. Therefore, crime prevention in China has more social and political significance than just reducing crime.     

DOES CRIME JUST MOVE AROUND THE CORNER? A CONTROLLED STUDY OF SPATIAL DISPLACEMENT AND DIFFUSION OF CRIME CONTROL BENEFITS*

Recent studies point to the potential theoretical and practical benefits of focusing police resources on crime hot spots. However, many scholars have noted that such approaches risk displacing crime or disorder to other places where programs are not in place. Although much attention has been paid to the idea of displacement, methodological problems associated with measuring it have often been overlooked. We try to fill these gaps in measurement and understanding of displacement and the related phenomenon of diffusion of crime control benefits. Our main focus is on immediate spatial displacement or diffusion of crime to areas near the targeted sites of an intervention. Do focused crime prevention efforts at places simply result in a movement of offenders to areas nearby targeted sites—“do they simply move crime around the corner”? Or, conversely, will a crime prevention effort focusing on specific places lead to improvement in areas nearby—what has come to be termed a diffusion of crime control benefits? Our data are drawn from a controlled study of displacement and diffusion in Jersey City, New Jersey. Two sites with substantial street‐level crime and disorder were targeted and carefully monitored during an experimental period. Two neighboring areas were selected as “catchment areas” from which to assess immediate spatial displacement or diffusion. Intensive police interventions were applied to each target site but not to the catchment areas. More than 6,000 20‐minute social observations were conducted in the target and catchment areas. They were supplemented by interviews and ethnographic field observations. Our findings indicate that, at least for crime markets involving drugs and prostitution, crime does not simply move around the corner. Indeed, this study supports the position that the most likely outcome of such focused crime prevention efforts is a diffusion of crime control benefits to nearby areas.     

少一些法律，多一些秩序——中西方犯罪预防策略的考察与批评

考察西方犯罪预防策略的变迁，可以发现法律和刑罚在预防策略中具有十分重要的位置。但是20世纪80年代以来，另一种预防思维已经产生，这就是针对犯罪诱因的多机构协作模式，其特点是强调社会政策而非刑罚，强调非法律方法而非法律方法，强调社会秩序而非犯罪控制。考察西方犯罪预防策略的优缺点，可为我国犯罪预防策略提供借鉴。     

Can “disciplined passion” overcome the cynical view? An empirical inquiry of evaluator influence on police crime prevention program outcomes

Objectives

Investigate the degree and nature of influence that researchers have in police crime prevention programs and whether a high degree of influence is associated with biased reporting of results.

Methods

Meta-analytic inquiry of experimental and quasi-experimental studies (n?=?42), drawn from four Campbell Collaboration systematic reviews of leading police crime prevention strategies: problem-oriented policing, ??hot spots?? policing, ??pulling levers?? policing, and street-level drug enforcement.

Results

Larger program effects are not associated with studies with higher involvement on the part of the evaluator (e.g., assisting in strategy design, monitoring implementation, overcoming implementation problems).

Conclusions

This study does not find support for the cynical view, which holds that researchers have a personal stake in the program or are pressured to report positive results. Importantly, the evaluator??s involvement in the implementation of the program may be a necessary condition of successfully executed police experiments in complex field settings.     

DETERRENCE,CRIMINAL OPPORTUNITIES,AND POLICE

In this article, we join three distinct literatures on crime control—the deterrence literature, the policing literature as it relates to crime control, and the environmental and opportunity perspectives literature. Based on empirical findings and theory from these literatures, we pose a mathematical model of the distribution of criminal opportunities and offender decision making on which of those opportunities to victimize. Criminal opportunities are characterized in terms of the risk of apprehension that attends their victimization. In developing this model, our primary focus is on how police might affect the distribution of criminal opportunities that are attractive to would‐be offenders. The theoretical model we pose, however, is generalizable to explain how changes in other relevant target characteristics, such as potential gain, could affect target attractiveness. We demonstrate that the model has important implications for the efficiency and effectiveness of police deployment strategies such as hot spots policing, random patrol, and problem‐oriented policing. The theoretical structure also makes clear why the clearance rate is a fundamentally flawed metric of police performance. Future research directions suggested by the theoretical model are discussed.