By Andrew Bacher-Hicks and Elijah de la Campa

Millions of Americans—particularly young men of color—are stopped on the street by police
each year. This form of proactive policing has been embraced by cities across the country as a
way to maintain order in high-crime neighborhoods and deter more serious crimes before they
occur. However, civilian stops rarely lead to an arrest and little is known about the social
impacts of frequent, unproductive interactions with police. In this paper, we leverage the quasi-
random movement of New York City police commanders across police precincts to estimate the
net impact of stop and frisk policing on students’ long-run educational attainment. We find that
a commander’s predicted effects on stops—based on data from one precinct—is highly predictive of changes in average stops after that commander enters a new precinct. We find that increased exposure to police stops has negative effects on high school graduation, college enrollment, and college persistence. These effects are substantially larger for black students, the racial group overwhelmingly stopped by police. However, we also find increases in overall school safety and evidence of positive spillovers for white and Asian students, who are less likely to interact with the police directly. These results highlight the social effects of criminal justice policy and have important implications for inequality.

Working paper, 2020. 60p.

By Aaron Chalfin and Maxim N. Massenkoff

In 2015, for the first time in nearly forty years, the rate of motor vehicle fatalities for Black Americans exceeded that of white Americans. By 2020, the gap in death rates stood at 34%, accounting for approximately 4,000 excess deaths between 2014 and 2020. This disproportionate increase occurred in nearly all states, in rural as well as urban areas, and was shared by drivers of all ages and genders. We consider a variety of potential explanations for the emerging race gap including race-specific changes in time spent driving, the circumstances of driving, the quality of medical care for crash victims, decreases in other types of mortality, changes in policing, and risky driving behaviors such as speeding, driving without a seat belt and driving while intoxicated. We can rule out many of these factors as important contributors to the race gap, but find evidence for two of them. The first is opportunity: Relative to white Americans, Black Americans are spending more time in vehicles than they have in the past. Changes in time spent driving, while modest, likely explain an important share of the emergent race gap. The second is a relative increase in drug use, manifested by a quadrupling of the rate of overdose deaths among Black Americans after 2014. Increased drug use appears to have resulted in a concomitant increase in fatal crashes involving drivers under the influence of drugs. Finally, we consider whether the emerging race gap is explained by the so-called "Ferguson effect," the idea that police officers have pulled back from enforcement activity in recent years. On the one hand, traffic stops

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  made by police officers do appear to have declined after 2014. However, the decline in traffic stops does not appear to be race-specific and there is little evidence of a broad increase in risky driving behaviors like speeding and driving without a seat belt.

Cambridge, MA: National Bureau of Economic Research, 2022. 58p.

By Desmond Ang and Jonathan Tebes

Roughly a thousand people are killed by American law enforcement officers each year, accounting for more than 5% of all homicides. We estimate the causal impact of these events on civic engagement. Exploiting hyper-local variation in how close residents live to a killing, we find that exposure to police violence leads to significant increases in registrations and votes. These effects are driven entirely by Blacks and Hispanics and are largest for killings of unarmed individuals. We find corresponding increases in support for criminal justice reforms, suggesting that police violence may cause voters to politically mobilize against perceived injustice.

Unpublished paper, 2021. 30p.

By National Academies of Sciences, Engineering, and Medicine. 

The US Department of State, Bureau of International Narcotics and Law Enforcement (INL) provides assistance and supports capacity building for criminal justice systems and police organizations in approximately 90 countries. In order to support and inform that work, this report explores high-level corruption and its effects on police organizations, as well as strategies that police can use to effectively contribute to efforts to combat that corruption.

Washington, DC: National Academies Press, 2022. 74p.

By National Academies of Sciences, Engineering, and Medicine.

Scholars, policymakers, and the public view police legitimacy and community trust in the police alike as essential components of an effective police organization. An extensive network of international and regional organizations, bilateral donors, international financial institutions, and civil society organizations aims to work with governments to improve policing practices and enhance police legitimacy. As a part of that network, the U.S. Department of State, through its Bureau of International Narcotics and Law Enforcement Affairs (INL), provides foreign assistance to and supports capacity building for criminal justice systems and police organizations in approximately 90 countries. Like many donors, it strives to direct its resources to the most effective approaches to achieve its mission. At the request of INL, the Committee on Law and Justice of the National Academies of Sciences, Engineering, and Medicine convened an ad hoc committee to review, assess, and reach consensus on existing evidence on policing institutions, police practices and capacities, and police legitimacy in the international context. The committee produced five reports, addressing questions of interest to INL and the State Department. Developing Policing Practices that Build Legitimacy, the fourth in this series, responds to the question: What policing practices build community trust and legitimacy in countries with low-to-moderate criminal justice sector capacity? This report focuses on the concept of legitimacy and ways of building legitimacy to foster this kind of trust and expectations.

Washington, DC: National Academies Press, 2022. 66p.

By National Academies of Sciences, Engineering, and Medicine.

Training police in the knowledge and skills necessary to support the rule of law and protect the public is a substantial component of the activities of international organizations that provide foreign assistance. Significant challenges with such training activities arise with the wide range of cultural, institutional, political, and social contexts across countries. In addition, foreign assistance donors often have to leverage programs and capacity in their own countries to provide training in partner countries, and there are many examples of training, including in the United States, that do not rely on the best scientific evidence of policing practices and training design. Studies have shown disconnects between the reported goals of training, notably that of protecting the population, and actual behaviors by police officers. These realities present a diversity of challenges and opportunities for foreign assistance donors and police training. At the request of the U.S. State Department's Bureau of International Narcotics and Law Enforcement Affairs, the Committee on Law and Justice of the National Academies of Sciences, Engineering, and Medicine examined scientific evidence and assessed research needs for effective policing in the context of the challenges above. This report, the second in a series of five, responds to the following questions: What are the core knowledge and skills needed for police to promote the rule of law and protect the population? What is known about mechanisms (e.g., basic and continuing education or other capacity building programs) for developing the core skills needed for police to promote the rule of law and protect the population?

Washington, DC: The National Academies Press. 2022. 102p.

By National Academies of Sciences, Engineering, and Medicine

The movement for evidence-based policing in the 1990s came on the heels of the concept of evidence-based medicine in the same decade, but with far less clinical research to apply in policing practices. Since then, police research findings have been growing at a rapid rate and have been reviewed by the National Academies of Sciences, Engineering, and Medicine on repeated occasions in the last two decades. However, scant research findings have been reported at the country level, examining differences in police systems and policies across nations. In an era when the U.S. Congress has mandated better evidence to support public expenditure, the application of that mandate to overseas police development requires two responses. One is to do the best translation possible from existing research comparing differences between and within countries. The other is to map out research and action agendas that will promote the growth of new evidence to provide better guidance to policing in the international context. This report is the first of five by a committee with diverse kinds of policing expertise assembled for the task by the National Academies. All five of these reports will be completed at the request of the International Narcotics and Law Enforcement (INL) Bureau of the U.S. Department of State. The committee was charged by INL to identify good practices in police reform. INL’s goal is for our reports to help ensure that ongoing U.S. foreign assistance for organizational police capacity building is informed by research. At the same time, INL seeks guidance from lessons learned from practitioners. Linking the two kinds of knowledge is an ongoing challenge in policing. Addressing this challenge requires a consensus-building process that identifies and then weighs the strength of relevant evidence, debates the conclusions, and engages a wide group of users to ensure that its presentation is relevant and accessible to them. The project, beginning with this report, offers a unique opportunity to unite the research and practitioner perspectives for actionable recommendations that can strengthen the assistance provided for international policing.

Washington, DC: The National Academies Press, 2022. 120p.

By Susannah N. Tapp and Elizabeth J. Davis

In 2020, an estimated 21% of U.S. residents age 16 or older (about 53.8 million persons) reported experiencing contact with police during the past 12 months (figure 1), down from 24% in 2018. Approximately 10% of residents had experienced a police-initiated contact in 2020, while 11% experienced a resident-initiated contact and 3% were involved in a traffic accident that led to a police contact. Findings in this report are based on data from the Bureau of Justice Statistics’ (BJS) 2020 Police-Public Contact Survey (PPCS), with selected data from the 2018 and 2015 PPCS data collections. The PPCS is a supplement to the National Crime Victimization Survey (NCVS), which collects information from a nationally representative sample of persons age 12 or older in U.S. households. The PPCS collects information from persons age 16 or older on nonfatal contacts with police during the 12 months prior to the interview. Police contacts were classified by the year of the survey and not by the year of the contact.

Washington, DC: U.S. Bureau of Justice Statistics, 2022. 25p.

By Fernando Saltiel and Cody Tuttle

We show that the quality of police hires varies over the business cycle. Officers hired when the unemployment rate is high have fewer complaints, disciplines, and are less likely to be fired than officers hired when the unemployment rate is low. Effects are larger for younger workers who have weaker outside options in recessions. We find that the size and quality of the applicant pool increases in high unemployment years–more people take entry exams and a smaller fraction fail the exam. Our findings shed light on how outside options affect police hires and speak to policy questions about police recruitment.

Bonn: IZA – Institute of Labor Economics 2022. 48p.

By Aaron Stagoff-Belfort, Daniel Bodah, and Daniela Gilbert

As policymakers and the public consider how best to address crime nationwide, deeper insights on policing should guide decisions about its funding and role in the provision of public safety. An assumption that policing is cost-effective may guide decisions to provide law enforcement with additional resources, yet a range of policing activities can result in “social costs of policing”: people suffering physical and behavioral health problems; losing educational opportunities, jobs, housing, and transportation; and withdrawing from civic engagement. These effects stem not only from violent interactions with police, but also from indirect exposure to routine policing activities; for instance, living in a neighborhood where police stop many people on the street. Even being arrested but not convicted and not having any continuing criminal legal system involvement can cause significant harm. This evidence brief seeks to fill a critical gap in understanding the benefits and costs of relying on policing as a primary approach to safety. When we measure what effect policing has on public safety, we must include the social costs of policing that make communities less healthy and prosperous, and consider whether the crime reduction benefits that policing can provide may be achieved through less costly means. The American Public Health Association has declared police violence—which often stems from encounters over minor infractions—a public health issue. Beyond acts of police brutality, routine law enforcement actions such as arrests and street stops can also destabilize communities.

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  Such activities are common: in the United States, more than nine million arrests are made annually—one every three seconds—though 80 percent of those are for low-level offenses, and only five percent are for serious violent crimes. Responding to social problems through policing is a policy choice, and arrests.

New York: Vera Institute of Justice, 2022. 33p.

By Andrew Bacher-Hicks and Elijah de la Campa

In an effort to thwart crimes in progress and deter future incidents, police in the US conduct
millions of civilian street stops each year. Though this practice is commonplace in most large
urban police departments, little is known about the net impact of this strategy on crime. This
paper exploits the naturally-occurring movement of New York Police Department commanders
during the height of New York City’s Stop and Frisk program to estimate commanders’ effects on
civilian stops and their subsequent impact on crime. We generate predictions of commanders’ effects on stops in a precinct, conditional on neighborhood demographics, crime rates, and policing strategies. Commanders’ effects—estimated using data only from tenures in prior precincts—are highly predictive of observed stops in new precincts, which highlights the transferability of commanders’ tactical preference for stops. We find that a high-stop strategy decreases misdemeanor crime within a precinct, but has no effect on more serious felony offenses. Moreover, we find suggestive evidence that the decrease in misdemeanor offenses is partially offset by crime displacement to adjacent neighborhoods. We conclude by demonstrating that commander stop effects are uncorrelated with their effects on other proactive policing strategies, and that commanders trade off their ability to build police legitimacy in the community with their preference for stops. Contrary to broken windows theory, our findings suggest that stop and frisk tactics do not deter more

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  serious criminal behavior, and thus, police should consider alternatives to strategies that emphasize the proactive enforcement of low-level offenses.

Unpublished paper 2020. 71p.

By Peter Manning

With the rise of surveillance technology in the last decade, police departments now have an array of sophisticated tools for tracking, monitoring, even predicting crime patterns. In particular crime mapping, a technique used by the police to monitor crime by the neighborhoods in their geographic regions, has become a regular and relied-upon feature of policing. Many claim that these technological developments played a role in the crime drop of the 1990s, and yet no study of these techniques and their relationship to everyday police work has been made available. Noted scholar Peter K. Manning spent six years observing three American police departments and two British constabularies in order to determine what effects these kinds of analytic tools have had on modern police management and practices. While modern technology allows the police to combat crime in sophisticated, detail-oriented ways, Manning discovers that police strategies and tactics have not been altogether transformed as perhaps would be expected. In The Technology of Policing, Manning untangles the varying kinds of complex crime-control rhetoric that underlie much of today's police department discussion and management, and provides valuable insight into which are the most effective—and which may be harmful--in successfully tracking criminal behavior.

New York: New York University Press, 2011. 338p.

By Canice Prendergast

We study LAPD police reforms after the Rampart scandal, when formal oversight rose discretely in 1998, and then fell in late 2002. We offer a simple model to interpret how police behavior is affected by changed accountability to the public. We show how officers responded by a practice they labeled “drive and wave”. The arrest-to-crime rate fell 40% after accountability to the public rose, then rebounded to its original level when accountability fell. For the “victimless” crimes of narcotics and prostitution, arrests fall almost 50% and then rebound. No such effects arise for the Los Angeles Sheriff Department, even for those stations surrounded by areas policed by the LAPD. We also see no effects on arrests made by other agencies within the LAPD’s jurisdiction. This impact was greatest in predominantly Hispanic neighborhoods, and felt least in White communities. Other behavioral responses - use of force and street stops - tell a similar story. We argue that much of the response may be attributable to an imbalance between oversight done by suspects compared to that done by the victims of crime. We also document an impact on homicides.

Chicago: University of Chicago Booth School of Business, Stigler Center for the Study of the Economy and the State, 2021. 63p.

By Taeho Kim

Body-worn cameras (BWCs) have received extensive attention as a key reform to restore police legitimacy. I study the causal effects of BWCs on law enforcement outcomes by conducting a nationwide study of BWCs across 947 agencies that adopted BWCs between 2014 and 2016 in the US. I find that BWCs led to decreases in the use of force but the increased oversight did not reduce crime control activities. By examining social media usage from Twitter, I also find suggestive evidence that BWC adoption has improved public opinion toward the police.

Unpublished paper, 2019. 84p.

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

Body-worn cameras do not have clear or consistent effects on most officer or citizen behaviors, but different practices need further evaluation. 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.

Campbell Systematic Review, 2020. 40p.

By The International Association of Chiefs of Policy (IACP)

As part of our long-standing commitment to advancing the profession of law enforcement and the practice of policing, eleven leading law enforcement leadership and labor organizations continued their work to provide guidance to the law enforcement profession on de-escalation techniques, less-lethal force, and deadly force. The extensive work of the participating organizations resulted in the development of a companion Discussion Paper to supplement the Consensus Policy on Use of Force that was originally published in 2017 and updated in 2020. The combined document represents our collaborative efforts to advance the law enforcement profession, while upholding our commitment and duty to serve the public and preserve all human life. The National Consensus Discussion Paper on Use of Force is designed to provide essential background material and supporting documentation to promote greater understanding of the developmental philosophy and implementation guidelines for the Consensus Policy. Law agencies are encouraged to utilize the Discussion Paper and the information contained therein to better inform their decisions on whether to implement the various elements found in the Consensus Policy in their own agencies.

Alexandria, VA: IACP, 2020. 16p.

By Li Sian Goh

Despite the widespread implementation of new policies intended at reducing police officers’ use of force in encounters with civilians, evidence about these policies remains patchy. Consisting of a series of three papers, my dissertation seeks to contribute to the body of knowledge on measures to reduce police use of force. The first paper considers the effect of consent decrees and other forms of federal intervention on fatalities resulting from citizen encounters with the police. Using a panel dataset of deaths caused by the police between the years 2000 and 2016, a difference-in-differences analysis found that court-appointed monitorships reduced fatalities by 29.1%. The second paper examines the effect of departmental oversight over body-worn cameras on officer-involved shootings. Using a panel dataset of police departments in 36 large departments across the United States, a difference-in-differences analysis finds that while the presence of body-worn cameras alone did not reduce shootings, restricting officer discretion on when cameras should be activated reduced shootings by 33.3%. The final paper evaluates the effect of a de-escalation training program. A difference-in-differences analysis of individual officers revealed no significant changes in serious force levels between officers who had been trained and officers who had not been trained. However, an analysis comparing the department which implemented the training with other law enforcement agencies in the same state suggested that serious force rates declined by approximately 40%. In totality, the dissertation

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  provides evidence about the effectiveness of contemporary measures to reduce use of force.

Philadelphia: University of Pennsylvania, 2020. 171p.

By Julie Ciccolini, Ida Sawyer and Madeline de Figueiredo

On June 4, 2020, New York City police carried out a planned assault and mass arrests of peaceful protesters in the Mott Haven neighborhood of the South Bronx, a low-income Black and brown community that has long faced systemic racism and police brutality. The operation was among the most aggressive police responses to protests across the United States following the police killing of George Floyd in Minneapolis, Minnesota on May 25. About 10 minutes before the 8 p.m. curfew, scores of police officers surrounded and trapped the roughly 300 protesters, not allowing them to disperse. Just after 8 p.m., the police, unprovoked and without warning, advanced on the protesters, whaling their batons, beating people from car tops, and firing pepper spray into people’s faces before rounding up about 250 of them for arrest. Clearly identifiable legal observers and street medics were also targeted. “Kettling” Protesters in the Bronx, based on interviews or written accounts from 81 protesters and observers and analysis of 155 videos recorded during the protest, reveals how the police action in Mott Haven was deliberate, planned and in violation of international human rights law. The operation illustrates a culture within the New York police force, modeled by top commanders, that encourages and condones violence and abuse. The report describes the government’s ineffective accountability mechanisms that protect police officers, shows the shortcomings of incremental reforms, and makes the case for structural change.

New York: Human Rights Watch and the American Civil Liberties Union, 2020. 114p.

By Thomas Woodmansee, John Markovic

As more police agencies have adopted BWCs on their own initiative, and at least seven states have recently moved to mandate their use, BWCs are becoming a permanent fixture for the majority of police agencies. As BWCs continue to garner widespread support across varied segments of the public and of law enforcement, the benefits of this technology are becoming firmly established and agencies are demonstrating novel ways to use BWCs to improve policing. The context in which agencies implement BWCs is important, and police understand that BWCs are quickly becoming another component of the required “toolbelt” that they take into the field every day. Command staff now realize that BWCs are part of the fabric of their policing operations, i.e., BWCs are affected by and are affecting many other dimensions of policing. BWCs have, for instance, added to police workload by generating public and media requests for footage that must be painstakingly reviewed and redacted before release. On the positive side, departments have realized some areas where BWCs serve to streamline existing practices, such as the investigation and resolution of citizen complaints. At the same time agencies also recognize some previously unidentified and unintended benefits of this technology. BWCs provide police with opportunities to enhance their patrol responses and investigations. In this article written by CNA's Thomas Woodmansee and BJA's John Markovic, we discuss these two applications and other unique benefits of BWCs.

2022. 9p.

By Craig D. Uchida; Shellie E. Solomon, Christine Connor, John McCluskey, Charles M. Katz, Michael D. White, Quin Patterson, Allie Land, John Markovic, with Kyle Anderson & Jennifer Schmitz

Digital Evidence Management (DEM) encompasses a wide variety of devices, technologies, tools, and data, particularly as they relate to the criminal justice system (Goodison, Davis, and Jackson, 2015). This report is about body-worn cameras (BWCs) and the digital evidence (footage) created by the technology. The main purpose of the study is to understand and explain the key challenges faced by law enforcement agencies and prosecutor offices as they use BWCs routinely. Taking a case study approach, we examine the process for managing BWC footage in seven agencies: Two large police departments (Phoenix, AZ and Los Angeles, CA); two mid-size police agencies (Glendale, AZ and Rochester, NY); a Sheriff's Office (Harris County, TX), and a collaborative effort in South Florida (Broward County State Attorney's Office and Fort Lauderdale Police Department).

Silver Spring, MD: Justice and Security Strategies, 2022. 83p.