By Magnus Lofstrom, Joseph Hayes, Brandon Martin, and Deepak Premkumar, with research support from Alexandria Gumbs

In this report, we analyze data for almost 4 million stops by California’s 15 largest law enforcement agencies in 2019, examining the extent to which people of color experience searches, enforcement, intrusiveness, and use of force differently from white people. While it is important to caution the reader that analysis of these differences is not causal, our analysis—which focuses in particular on differences between Black and white Californians—reveals notable differences.Black Californians are more than twice as likely to be searched as white Californians, at about 20 percent versus 8 percent of all stops. …hese disparities are driven primarily by traffic stops made by the 14 data-contributing police and sheriff departments (as compared with the California Highway Patrol). These findings can provide guidance for discussing which stops can safely be reduced to mitigate racial inequities, which may also reduce risks and injuries to both officers and civilians.

San Francisco, CA Public Policy Institute of California, 2021. 30p.

By Jeremy West

Nonrandom selection into police encounters typically complicates evaluations of law enforcement discrimination. This study overcomes selection concerns by examining automobile crash investigations, for which officer dispatch is demonstrably independent of drivers’ race. I find State Police officers issue significantly more traffic citations to drivers whose race differs from their own. This bias is evident for both moving and nonmoving violations, the latter indicating a preference for discriminatory leniency towards same-race individuals. I show this treatment is unmitigated by socioeconomic factors: officers cite other-race drivers more frequently regardless of their age, gender, vehicle value, or characteristics of the local community.

Santa Cruz, CA: Economics Department, University of California at Santa Cruz , 2018. 37p.

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 The Expert Review Panel

The concerns identified in this report, though not unique, are serious and will require significant attention by the Department’s leadership and the City. There is important learning from the reforms being undertaken by other agencies for Fort Worth as it continues its efforts to operate according to its stated values and policies. The Department has many characteristics of a modern, professional police department. The leadership of the Department revised its policies and procedures in an effort to conform to nationally recognized best practices. In place are the basic structures, accountability committees, and review processes that one would expect in a department of its size. It has built a new academy and converted its training curriculum away from a military style boot camp to a scenario and classroom-based academic setting. Investments in technology have given managers the tools necessary to effectively and efficiently hold officers accountable to policy and law, as well as to identify and address gaps in policy, training, supervision, or widespread practices. Both the Department’s and the City’s leadership have taken steps to create legitimacy in all of Fort Worth’s communities. …. However, the actual experience of some members of the community, especially people of color and those in low-income neighborhoods, is very different. Daily encounters are far too often characterized by a “command and control” approach to policing that leads to avoidable uses of force and creates tension with residents who encounter police officers. The failure to use effective de-escalation techniques continues to be a significant issue that has increased mistrust. Accountability for aggressive police tactics is frequently anemic or ineffective and can place form over substance, missing both individual and systemic problems. Compounding the issue, the Panel heard reports from supervisors in the Department that middle managers were discouraged from raising issues unless there had been a complaint or a public outcry.

Fort Worth, TX: Expert Review Panel, 2022. 97p.

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 David L. Carter

Law Enforcement Intelligence: A Guide for State, Local, and Tribal Law Enforcement Agencies is a policy oriented review of current initiatives, national standards, and best practices. The first two chapters provide definitions and context for the current state of law enforcement intelligence. Chapter 2 also provides a discussion of homeland security—or “all-hazards”—intelligence. While more law enforcement agencies and fusion centers are embracing the all-hazards approach, its application remains somewhat unclear. This discussion provides a framework for homeland security intelligence policy. Chapter 3 is a historical perspective that has multiple purposes. First, it provides a discussion of past abuses by law enforcement intelligence because it is important to understand the problems of the past in order to prevent them in the future. Next, the chapter provides a framework for national recommendations and professional standards for the practice of intelligence. Finally, the discussion identifies the various working groups and committees that are framing the current intelligence model and the relationship of those groups to federal agencies and professional law enforcement organizations. Fundamental to all types of intelligence is a system for managing the flow of information for analysis. This is alternately called the Intelligence Process or the Intelligence Cycle. Chapter 4 is a descriptive discussion of the process as it applies to law enforcement agencies. While there are different models for the Intelligence Process, this discussion relies on the model used in the National Criminal Intelligence Sharing Plan. Recommendations from both the National Criminal Intelligence Sharing Plan and the COPS Office-funded International Association of Chiefs of Police intelligence summits urge law enforcement agencies to adopt Intelligence-Led Policing (ILP). The challenge, however, is that there is no universally accepted definition or process for understanding and implementing ILP. Chapters 5 and 6 amalgamate the diverse literature on ILP to provide a holistic view. Chapter 5 focuses on the concept of ILP as it applies to American law enforcement, with a perspective on the British approach from which the concept originated. Chapter 6 focuses on the organizational and administrative processes for implementing ILP.

Washington, DC: U. S. Department of Justice Office of Community Oriented Policing Services, 2009. 496p.

By Dermot S. Barr

This thesis explores the intergroup dynamics during the development of rioting at two sites in Greater Manchester in 2011, Pendleton, in Salford, and Manchester city centre. The primary theoretical contribution of this thesis is to the Elaborated Social Identity Model of the development of conflict (ESIM, Drury & Reicher 2000). Through detailed analysis of how the intergroup dynamics informed the development of the two riots, and participants’ subjective experiences, the thesis confirms and extends the ESIM understandings of the social psychological processes involved in escalating intergroup conflict.

Manchester, UK: University of Manchester, 2018. 420p

By Charles Branas, Shani Buggs, Jeffrey A. Butts, Anna Harvey, Erin M. Kerrison, Tracey Meares, Andrew V. Papachristos, John Pfaff, Alex R. Piquero, Joseph Richardson Jr., Caterina Gouvis Roman, and Daniel Webster

This report summarizes the collective judgment of an experienced group of researchers who were free to consider all evidence, unconstrained by the conventional priority given to randomized controlled trials (RCT). The most rigorous studies in the field of community violence are RCTs, but many focus on individual behaviors only, failing to account for the full social context giving rise to those behaviors, including social and economic inequities, institutionalized discrimination, and the racial and class biases of the justice system itself. To synthesize evidence in an inclusive manner, one must be aware of social context and prioritize solutions that help to address structural impediments while still providing immediate interventions to reduce violence. Unless research evidence is considered in this context, potentially effective strategies may be overlooked simply because they target community-level change rather than individual change, and for that reason are difficult to evaluate and the research literature to back them up is inevitably less rigorous and less prominent.

New York: John Jay College Research Advisory Group on Preventing and Reducing Community Violence, 2020. 42p.

By Lorraine Mazerolle,Adrian Cherney,Elizabeth Eggins,Lorelei Hine and Angela Higginson

Multiagency responses to reduce radicalisation often involve colla-borations between police, government, nongovernment, business and/or community organisations. The complexities of radicalisation suggest it is impossible for any single agency to address the problem alone. Police‐involved multiagency partner-ships may disrupt pathways from radicalisation to violence by addressing multiple risk factors in a coordinated manner.Objectives:1. Synthesise evidence on the effectiveness of police‐involved multiagency interventions on radicalisation or multiagency collaboration. Qualitatively synthesise information abouthowthe intervention works (me-chanisms), interventioncontext(moderators), implementation factors and eco-nomic considerations.Search Methods:Terrorism‐related terms were used to search the Global PolicingDatabase, terrorism/counterterrorism websites and repositories, and relevantjournals for published and unpublished evaluations conducted 2002–2018. Thesearch was conducted November 2019. Expert consultation, reference harvestingand forward citation searching was conducted November 2020.Selection Criteria:Eligible studies needed to report an intervention where policepartnered with at least one other agency and explicitly aimed to address terrorism,violent extremism or radicalisation. Objective 1 eligible outcomes included violentextremism, radicalisation and/or terrorism, and multiagency collaboration. Only impact evaluations using experimental or robust quasi‐experimental designs were eligible. Objective 2 placed no limits on outcomes. Studies needed to report anempirical assessment of an eligible intervention and provide data on mechanisms,moderators, implementation or economic considerations.Data Collection and Analysis:The search identified 7384 records. Systematic screening-identified 181 studies, of which five were eligible for Objective 1 and 26 for Objective 2.

Oslo, Norway: Campbell Collaborative, 2021. 88p.

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 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.