By Roland G. Fryer, Jr

This paper explores racial differences in police use of force. On non-lethal uses of force, blacks and Hispanics are more than fifty percent more likely to experience some form of force in interactions with police. Adding controls that account for important context and civilian behavior reduces, but cannot fully explain, these disparities. On the most extreme use of force – officer-involved shootings – we find no racial differences in either the raw data or when contextual factors are taken into account. We argue that the patterns in the data are consistent with a model in which police officers are utility maximizers, a fraction of which have a preference for discrimination, who incur relatively high expected costs of officer-involved shootings.

Cambridge, MA: National Bureau of Economic Research, 2018. 57p.

By Travis Campbell

A difference-in-differences design finds census places with Black Lives Matter protests experience a 15% to 20% decrease in police homicides over the ensuing five years, around 300 fewer deaths. The gap in lethal use-of-force between places with and without protests widens over these subsequent years and is most prominent when protests are large or frequent. This result holds for alternative specifications, estimators, police homicide datasets, and population screens; however, it does not hold if lethal use-of-force is normalized by violent crime or arrests. Protests also influence local police agencies, which may explain the reduction. Agencies with local protests become more likely to obtain body-cameras, expand community policing, receive a larger operating budget, and reduce the number of property crime-related arrests, but forgo some black officer employment and college education requirements.

Working paper, 2021. 65p.

By Anthony Braga; James R. Coldren Jr.; William Sousa; Denise Rodriguez and Omer Alper

This study reports the findings of a randomized controlled trial involving more than 400 police officers in the Las Vegas Metropolitan Police Department (LVMPD). The authors find that BWC-wearing officers generated significantly fewer complaints and use of force reports relative to control officers without cameras. BWC-wearing officers also made more arrests and issued more citations than their non-BWC-wearing controls. In addition, a cost-benefit analysis revealed that savings from reduced complaints against officers, and the reduced time required to resolve such complaints, resulted in substantial cost savings for the police department. Considering that LVMPD had already introduced reforms regarding use of force through a Collaborative Reform Initiative prior to implementing body worn cameras, these findings suggest that body worn cameras can have compelling effects without increasing costs.

Arlington, VA: CNA Analysis and Solutions, 2017. 80p.

By Justin E. Holz, Roman G. Rivera, and Bocar A. Ba

We study the link between officer injuries-on-duty and the force used by their peers using a network of officers who, through a random lottery, began the police academy together. We find that peer injuries on-duty increase the probability of using force by 7%. The effect is concentrated in a narrow time window near the event and is not associated with significantly lower injury risk to the officer. Complaints of improper searches and failure to provide service also increase after peer injuries, suggesting that the increase in force might be driven by heightened risk aversion.

Philadelphia: Faculty Scholarship at Penn Law, 2019. 63p.

The U.S. Department of Justice has dedicated $20 million to fund the purchase of and technical assistance for BWCs. In 2013, the Law Enforcement Management and Administrative Statistics survey estimated that about a third of local law enforcement agencies had already adopted BWCs, and this percentage has likely greatly increased since then. At the same time, this rapid adoption of BWCs is occurring within a low information environment; researchers are only beginning to develop knowledge about the effects, both intentional and unintentional, of this technology.…what research questions and types of research should be pursued and why? How can we build a translatable knowledge base that is responsive and rigorous? An important first step in answering these questions is to identify not only existing knowledge but also current projects underway to see research gaps and opportunities. Equally important in building the evidence-base for BWCs is ensuring that research is responsive to the needs and concerns of police and citizens and that it also anticipates future uses and concerns of BWCs. Many types of research might be needed, including process and outcome evaluations, national surveys on prevalence and use, studies about the possible consequences of that implementation for both.

Fairfax, VA: George Mason University, Center for Evidence-Based Crime Policy, 2015. 30p.

By Christopher S. Koper, Cynthia Lum, James J. Willis, Dan J. Woods and Julie Hibdon

Using a multi-method approach in four large law enforcement agencies, both urban and suburban, this study examined many of the social, organizational, and behavioral aspects of implementing police technologies, so as to make recommendations for optimizing the use of technology in policing.

The study consisted of officer surveys, field observations, interviews, focus groups, and experimental and quasi-experimental evaluations. It assessed the uses and impacts of several information, analytical, surveillance, and forensic technologies, including information technology (IT), mobile computing, crime analysis, and license plate readers. The study determined how these technologies affected policing operations, management, agency structure, culture, efficiency, effectiveness, citizen interaction, and job satisfaction. Overall, the study found that technology’s effects on policing are complex and often contradictory.

The recommendations for police agencies include a broad base of participation in the planning and implementation process for a new technology, involving those who will be affected by the technology; providing pilot testing and refinement of early versions of a technology; ensuring appropriate training in the characteristics and uses of the technology; and having a systematic and continuous follow-up, in-service training, ongoing technical support, and adaptation to lessons learned.

Fairfax, VA: George Mason University, Center for Evidence-Based Crime Policy 2016. 336p.

By Charles M. Katz, David E. Choate, Justin Ready and Lidia Nuno

Police Department $500,000 to purchase, deploy and evaluate police body worn cameras. The design and implementation of the project included the purchase of 56 BWC systems and deploying them in the Maryvale Precinct. The implementation of the BWC’s occurred in one of the two Maryvale Precinct squad areas (aka target area). All officers assigned to the target area were issued the equipment and were provided training in its use, maintenance, and related departmental policy. This evaluation was conducted to examine the effect of implementing police worn body cameras on complaints against the police and domestic violence case processing and outcomes.

Our analysis of the camera meta-data indicated that only 13.2 to 42.2 percent of incidents were recorded by and BWV camera. Domestic violence incidents were the most likely to be recorded (47.5%), followed by violent offenses (38.7), back-up (37%), status offenses (32.9%), and subject/vehicle stops (30.9%). ..Regardless, the officer worn body cameras were found to be beneficial to the officers and the court in a number of ways. … BWC did not appear, however, to have an impact on suspect behavior as measured through resisting arrest charges.Additionally, we examined the impact of body worn cameras on domestic violence case processing. Analysis of the data indicated that following the implementation of body cameras, cases were significantly more likely to be initiated, result in charges filed, and result in a guilty plea or guilt verdict.

Phoenix, AZ: Center for Violence Prevention & Community Safety, Arizona State University. 2014. 45p.

By Police Executive Research Forum

This report, the 30th in PERF’s Critical Issues in Policing series, represents the culmination of 18 months of research, field work, and national discussions on police use of force, especially in situations involving persons with mental illness and cases where subjects do not have firearms. The Critical Issues series has always focused on the most consequential emerging issues facing police agencies. In 2016, no issue is of greater consequence to the policing profession, or to the communities we serve, than the issue of police use of force. Beginning in the summer of 2014 and continuing over the past year and a half, our nation has seen a series of controversial cases, many of them captured on videos taken by the police, bystanders, or nearby security cameras. These events have sparked protests across the country and soul-searching among police executives. They have also threatened community-police relationships in many areas and have undermined trust. This report is grounded in four national conferences; a survey of police agencies on their training of officers on force issues; field research in police agencies in the United Kingdom and here at home; and interviews of police trainers and other personnel at all ranks, as well as experts in mental health

Washington, DC: Police Executive Research Forum, 2016. 136p.

By Christie Gardiner

This report describes the findings of a recent survey of a nationally-representative sample of local law enforcement agencies on the role of higher education in policing. The survey was completed by 958 agencies (116 which employ 250 or more officers and 842 which employ fewer than 250 officers) from every state in the nation. This is the largest and most comprehensive non-governmental study ever conducted on the role of higher education in policing on a national level. It is also the first study in forty years to provide substantial information about higher education policy and practice in small departments.

Washington, DC: Police Foundation, 2017. 76p.

By Cynthia Lum, Christopher S. Koper, David B. Wilson, Megan Stoltz, Michael Goodier, Elizabeth Eggins, Angela Higginson and Lorraine Mazerolle

Law enforcement agencies have rapidly adopted body-worn cameras (BWCs) in the last decade with the hope that they might improve police conduct, accountability, and transparency, especially regarding use of force. Overall, there remains substantial uncertainty about whether BWCs can reduce officer use of force, but the variation in results over studies suggests there may be conditions in which BWC could be effective. BWCs also do not seem to affect other police and citizen behaviors in a consistent manner, including officers’ self-initiated activities or arrest behaviors, dispatched calls for service, or assaults and resistance against police officers. BWCs can reduce the number of citizen complaints against police officers, but it is unclear whether this finding signals an improvement in the quality of police-citizen interactions or a change in reporting.

Research has not directly addressed whether BWCs can strengthen police accountability systems or police-citizen relationships. Overall, the way BWCs are currently being used may not substantially affect most officer or citizen behaviors. The use of BWCs does not have consistent or significant effects on officers’ use of force, arrest activities, proactive or self-initiated activities, or other measured behaviors. Nor do BWCs have clear effects on citizens’ calls to police or assaults or resistance against officers. Analysis suggests restricting officer discretion in turning on and off BWCs may reduce police use of force, but more assessment is needed.

Oslo, Norway: Campbell Collaborative, 2020. 40p.

By Chuka Emezue, Jo-Ana D. Chase,Tipparat Udmuangpia and Tina L. Bloom

A growing body of research shows the promise and efficacy of technology-based or digital interventions in improving the health and well-being of survivors of intimate partner violence (IPV). In addition, mental health comorbidities such as anxiety, post-traumatic stress disorder (PTSD), and depression occur three to five times more frequently in survivors of IPV than non-survivors, making these comorbidities prominent targets of technology-based interventions. Still, research on the long-term effectiveness of these interventions in reducing IPV victimization and adverse mental health effects is emergent. The significant increase in the number of trials studying technology-based therapies on IPV-related outcomes has allowed us to quantify the effectiveness of such interventions for mental health and victimization outcomes in survivors. This meta-analysis and systematic review provide critical insight from several randomized controlled trials (RCTs) on the overall short and long-term impact of technology-based interventions on the health and well-being of female IPV survivors.

Oslo, Norway: Campbell Collaborative, 2022. 69p.

By Joshua C. Hinkle, David Weisburd, Cody W. Telep and Kevin Petersen

POP is a proactive policing strategy developed by Herman Goldstein, who argued that the standard reactive model of policing was ineffective as it was overly focused on the means of policing (number of arrests, average response time, etc.) rather than the end goal of reducing crime and enhancing community safety. He suggested that police could be more effective if they were more proactive and researched root causes of crime, and developed tailor-made responses. This review assesses the effectiveness of POP interventions – defined as those programs which generally followed the tenets of the SARA model (scanning, analysis, response, assessment) developed by Spelman and Eck – in reducing crime and disorder and fear of crime, and improving citizen perceptions of police.

This update of a Campbell systematic review assesses the effectiveness of problem-oriented policing in reducing crime and disorder. It summarises the evidence from 34 studies: 28 from the USA, five from the UK and one from Canada.

Oslo, Norway: Campbell Collaboration, 2020. 86p.

By Robert J. Abbott

Founded by Peter the Great in 1718, Russia’s police were key instruments of tsarist power. In the reign of Alexander II (1855-1881), local police forces took on new importance. The liberation of 23 million serfs from landlord control, growing fear of crime, and the terrorist violence of the closing years challenged law enforcement with new tasks that made worse what was already a staggering burden. This book describes the regime’s decades-long struggle to reform and strengthen the police. The author reviews the local police’s role and performance in the mid-nineteenth century and the implications of the largely unsuccessful effort to transform them. From a longer-term perspective, the study considers how the police’s systemic weaknesses undermined tsarist rule, impeded a range of liberalizing reforms, perpetuated reliance on the military to maintain law and order, and gave rise to vigilante justice. While its primary focus is on European Russia, the analysis also covers much of the imperial periphery, discussing the police systems in the Baltic Provinces, Congress Poland, the Caucasus, Central Asia, and Siberia.

Budapest–Vienna–New York: Central European University Press, 2022. 235p.

By Morgan C. Williams Jr., Nathan Weil, Elizabeth A. Rasich, Jens Ludwig, Hye Chang, and Sophia Egrari

Body-worn cameras (BWCs) are an increasingly common tool for police oversight, accountability, and transparency, yet there remains uncertainty about their impacts on policing outcomes. This paper reviews what we know about the benefits of BWCs and how those benefits compare to the costs of this new technology. We make two contributions relative to existing research. First, we update prior meta-analyses of studies of the impacts of BWCs on policing outcomes to incorporate the most recent, and largest, studies carried out to date in this literature. This additional information provides additional support for the idea that cameras may affect a number of policing outcomes that are important from a social welfare perspective, particularly police use of force. Second, we carry out a benefit-cost analysis of BWCs, as financial barriers are often cited as a key impediment to adoption by police departments. Our baseline estimate for the benefit-cost ratio of BWCs is 4.95. Perhaps as much as one-quarter of the estimated benefits accrue to government budgets directly, which suggests the possibility that this technology could, from the narrow perspective of government budgets, even pay for itself.

Chicago: Becker Friedman Institute, University of Chicago, 2021. 32p.

By Philip Matthew Stinson, Sr., John Liederbach, Steven P. Lab and Steven L. Brewer, Jr

There are no comprehensive statistics available on problems with police integrity, and no government entity collects data on all criminal arrests of law enforcement officers in the United States. Police crimes are those crimes committed by sworn law enforcement officers with the general powers of arrest. These crimes can occur while the officer is either on- or off-duty and include offenses committed by officers employed by state and local law enforcement agencies. This study provides a wealth of data on a phenomena that relates directly to police integrity— data that previously did not exist in any useable format. The first goal of the study is to determine the nature and extent of police crime in the United States. The objective for this goal is to determine the incidence and prevalence of officers arrested. A second goal is to determine what factors influence how an agency responds to arrests of its officers.

Bowling Green, OH: Bowling Green State University, 2016. 671p.

By Priscillia Hunt, Jessica Saunders and John S. Hollywood

Even though there is a growing interest in predictive policing, to date there have been few, if any, formal evaluations of these programs. This report documents an assessment of a predictive policing effort in Shreveport, Louisiana, in 2012, which was conducted to evaluate the crime reduction effects of policing guided by statistical predictions. RAND researchers led multiple interviews and focus groups with the Shreveport Police Department throughout the course of the trial to document the implementation of the statistical predictive and prevention models. In addition to a basic assessment of the process, the report shows the crime impacts and costs directly attributable to the strategy. It is hoped that this will provide a fuller picture for police departments considering if and how a predictive policing strategy should be adopted.

There was no statistically significant change in property crime in the experimental districts that applied the predictive models compared with the control districts; therefore, overall, the intervention was deemed to have no effect. There are both statistical and substantive possibilities to explain this null effect. In addition, it is likely that the predictive policing program did not cost any more than the status quo.

Santa Monica, CA: RAND, 2014. 88p.

ByTanaya Devi and Roland G. Fryer Jr,

This paper provides the first empirical examination of the impact of federal and state "Pattern-or-Practice" investigations on crime and policing. For investigations that were not preceded by "viral" incidents of deadly force, investigations, on average, led to a statistically significant reduction in homicides and total crime. In stark contrast, all investigations that were preceded by "viral" incidents of deadly force have led to a large and statistically significant increase in homicides and total crime. We estimate that these investigations caused almost 900 excess homicides and almost 34,000 excess felonies. The leading hypothesis for why these investigations increase homicides and total crime is an abrupt change in the quantity of policing activity. In Chicago, the number of police-civilian interactions decreased by almost 90% in the month after the investigation was announced. In Riverside CA, interactions decreased 54%. In St. Louis, self-initiated police activities declined by 46%. Other theories we test such as changes in community trust or the aggressiveness of consent decrees associated with investigations -- all contradict the data in important ways.

Cambridge, MA: National Bureau of Economic Research, 2020. 63p.

By Sungwoo Cho, Felipe Gonçalves, and Emily Weisburst

Do reductions in arrests increase crime? We study line-of-duty deaths of police officers, events that likely impact police behavior through increased fear but are unlikely to directly impact civilian behavior. Officer deaths cause significant short-term reductions in all arrest types, with the largest reductions in arrests for lower-level offenses. In contrast, we find no evidence of an increase in crime or a change in victim reporting through 911 calls. There is also no apparent threshold of arrest decline beyond which crime increases. Our findings suggest that enforcement activity can be reduced at the margin without incurring public safety costs.

Bonn, Germany: IZA – Institute of Labor Economics , 2021. 69p.

By Aaron Chalfin, David Mitre-Becerril and Morgan C. Williams, Jr.

In December 2014 and January 2015, police officers in New York City engaged in an organized slowdown of police work to protest the murder of two police officers who were targeted by a gunman while sitting in their patrol car. An influential 2017 article in Nature Human Behaviour studies the effect of the NYPD’s work slowdown on major crimes and concludes that the slowdown led to a significant improvement in public safety. Contrary to the remainder of the literature, the authors conclude that proactive policing can cause an increase in crime. We re-evaluate this claim and point out several fatal weaknesses in the authors’ analysis that call this finding into question. In particular, we note that there was considerable variation in the intensity of the slowdown across NYC communities and that the communities which experienced a more pronounced reduction in police proactivity did not experience the largest reductions in major crime. The authors’ analysis constitutes a quintessential example of an ecological fallacy in statistical reasoning, a logical miscalculation in which inferences from aggregated data are mistakenly applied to a more granular phenomenon. We raise several additional and equally compelling concerns regarding the tests presented in the paper and conclude that there is little evidence that the slowdown led to short-term changes in major crimes in either direction.

Department of Criminology, University of Pennsylvania. Department of Economics, Barnard College, Columbia University , 2021. 38p.

By Bocar A. Ba and Roman G. Rivera

Does policing the police increase crime? We avoid simultaneity effects of increased public oversight during a major scandal by identifying events in Chicago that only impacted officers’ self-imposed monitoring. We estimate crime’s response to self- and public-monitoring using regression discontinuity and generalized synthetic control methods. Self-monitoring, triggered by police union memos, significantly reduced serious complaints without impacting crime or effort. However, after a scandal, both civilian complaints and crime rates rise, suggesting that higher crime rates following heightened oversight results from de-policing and civilian behavior simultaneously changing. Our research suggests that proactive internal accountability improves police-community relations without increasing crime.

Philadelphia: University of Pennsylvania Carey Law School, 2019. 89p.