By New York University School of Law, Policing Project

In response to the Gideon’s Army report indicating racial disparities in traffic stops, and the shooting of Jocques Clemmons, the Nashville Mayor’s Office asked the Policing Project to help develop strategies to address the disparities and improve community-police relations in Nashville. The Policing Project is an organization devoted to front-end democratic accountability to assure just and effective policing. The Policing Project talked with dozens of Nashville residents about their experiences with policing. Based on those conversations, we proposed to conduct a thorough assessment of the costs and benefits of using traffic stops to address crime. And we suggested that the City create a Steering Committee to guide work around community-police engagement and policing in Nashville. We conducted the traffic stop data work in collaboration with the Stanford Computational Policy Lab (SCPL), whose researchers performed the analysis. (The SCPL team’s more detailed report is included here as Appendix B.) The Metropolitan Nashville Police Department (MNPD) provided the necessary data, and has from the beginning shown a strong commitment to re-evaluating its traffic stop strategies and developing alternatives that can achieve public safety with fewer social costs. As the SCPL report shows, and as we summarize below, there are indeed notable racial disparities in traffic stops in Nashville. These disparities are higher for traffic stops around non-moving violations, such as broken taillights or expired tags. Disparity, however, is not necessarily evidence of discrimination. Any number of neutral factors, including officer deployment patterns or differences in rates of offending, may explain these and other disparities in the criminal justice system. MNPD explains these racial disparities in traffic stops on the ground that officers go where the crime is, and that in Nashville, high-crime neighborhoods tend to have larger minority populations. The SCPL analysis bears this out. However, even controlling for crime, unexplained racial disparity still remains. More importantly, the SCPL report shows that traffic stops are not an effective strategy for reducing crime. In particular, MNPD’s practice of making large numbers of stops in high crime neighborhoods does not appear to have any effect on crime. We make a number of recommendations, including that MNPD: • reduce the number of traffic stops • acknowledge black residents have been disproportionately affected by MNPD’s stop practices • monitor racial disparities on an ongoing basis • redeploy officer resources toward more effective crime-fighting tools • consider adopting a Neighborhood Policing strategy • post its department policies online • conduct a review of certain key policies such as use of force • conduct a review of training around use of force, traffic stops, and procedural justice • adopt a body camera policy with attention to transparency regarding the release of body camera footage In addition, we suggest that Nashville engage in a public process of strategic planning around public safety, bringing together the voices of the community and MNPD officials in doing so.

New York: Policing Project, 2023. 27p.

By The United States Commission on Civil Rights,  Minnesota Advisory Committee 

The nature and scope of the problem. There will be no end to disparate policing, and the accompanying resentment in the community, until sufficient data can be collected to better inform both policymakers and the People who elect them. Disparate policing is abusive on many levels, affecting the individuals involved, reopening unhealed wounds left by historical injustices, and reminding entire communities that their lives don’t matter. The Committee found that the lack of political will at all levels of government to enforce the limits on police conduct is the major impediment to meaningful change that would address the Constitutional violations identified in this report.  

Minneapolis:: Minnesota Advisory Committee to the U.S. Commission on Civil Rights ,2022. 62p.

By David S. Abrams, Hanming Fang and Priyanka Goonetilleke

Police “stop-and-frisks” of pedestrians and motorists have become an increasingly controversial tactic, given low average rates of contraband discovery, incidents of abuse, and evidence of racial disparity. Study of the tactic by economists has been much influenced by Knowles, Persico, and Todd (2001; hereafter, KPT) who first suggested the use of a “hit rate” (contraband discovery rate per frisk) test to distinguish racial prejudice from statistical discrimination in highway searches by police officers. Models used by KPT and almost all subsequent literature (e.g., Anwar and Fang 2006) on the subject imply diminishing marginal returns to frisks. That is, if frisks decrease substantially, the rate of contraband discovery should rise, ceteris paribus. This is the first paper to test this assumption empirically using arguably exogenous variations in frisk rates (cf. Feigenberg and Miller 2022). 1 We study the period around the nationwide protests that followed the killing of George Floyd on May 25, 2020, after which police frisks dropped tremendously and rapidly. Using extremely granular data from Chicago, we find that hit rates increased as police frisks plunged, in line with the predictions of KPT.

AEA Papers and Proceedings 2022, 112: 178–183 ,2022. 7p.

By Kevin Petersen, David Weisburd, Sydney Fay, Elizabeth Eggins and Lorraine Mazzerole 

Police stops are associated with reductions in crime but also a broad range of negative individual-level outcomes.

Police stop interventions produce meaningful and significant reductions in crime without evidence of spatial displacement. However, people subject to stops are associated with significantly less desirable mental and physical health outcomes, attitudes toward police, and self-reported crime/delinquency. For some outcome measures, the negative effects of pedestrian stops are considerably more pronounced for youth, though the data did not permit a comparison of individual effects by race.

What is this review about?

Police stops have become one of the most controversial yet widely-used crime prevention strategies in modern policing. This intervention involves the police-initiated stop of an individual (or group of individuals) on the street, for the purpose of investigation and/or questioning. Police stops have been commonly used as a tactic to combat violent and gun-related crime.

Campbell Systematic Reviews. 2023;1

By Desmond Ang, Panka Bencsik, Jesse Bruhn and Ellora Derenoncourt

How do high-profile acts of police brutality affect public trust and cooperation with law enforcement? To investigate this question, we develop a new measure of civilian crime reporting that isolates changes in community engagement with police from underlying changes in crime: the ratio of police-related 911 calls to gunshots detected by ShotSpotter technology. Examining detailed data from eight major American cities, we show a sharp drop in both the call-to-shot ratio and 911 call volume immediately after the police murder of George Floyd in May 2020. Notably, reporting rates decreased significantly in both non-white and white neighborhoods across the country. These effects persist for several months, and we find little evidence that they were reversed by the conviction of Floyd’s murderer. Together, the results illustrate how acts of police violence may destroy a key input into effective law enforcement and public safety: civilian engagement and reporting.

Cambridge, MA: Working paper, Harvard Kennedy School, 2021. 27p.

By Greg Ridgeway

In 2002, the Cincinnati Police Department (CPD) joined with other agencies and organizations to improve police-community relations in the city. This report focuses on the analysis of racial disparities in traffic stops in Cincinnati. The authors find no evidence of racial differences between the stops of black and those of similarly situated nonblack drivers, but some issues can exacerbate the perception of racial bias.

Santa Monica, CA: RAND, 2009. 93p.

By Elizabeth Luh

Biased police officers may purposely mis-record, or mask, the race of citizens that they interact with in order to evade detection. Indeed, journalists uncovered widespread evidence of such masking among Texas Highway troopers from 2010 to 2015. I propose a new test of racial bias in the presence of masking that is more powerful than standard tests and is well-suited to explore the rich heterogeneity in bias. Using various data-driven techniques to detect masking, I estimate that 24% of 130,240 searches were masked, with over half being Hispanic drivers being mis-recorded as white when searches failed to turn up contraband. I find that Hispanic and white troopers are biased against non-white motorists, with Hispanic motorists being treated the most unfairly. Using my model, I also find evidence of institutional racial bias and ‘bad apple’ troopers across Texas.

Ann Arbor, MI: Department of Economics; University of Michigan at Ann Arbor2019. 45p.

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 Lynn Langton and Matthew Durose

Examines the characteristics and experiences of persons age 16 or older who were stopped by police during traffic and street stops, and their perceptions of police behavior and response during these encounters.

Examines the characteristics and experiences of persons age 16 or older who were stopped by police during traffic and street stops, and their perceptions of police behavior and response during these encounters. It describes the outcomes of traffic and street stops by the reason for the stop; demographic characteristics of the persons stopped; race or Hispanic origin of the officers; and whether a ticket was issued, a search was conducted, or force was used. It also describes variations in perceptions of the police across characteristics and outcomes of traffic and street stops. Data are from the 2011 Police-Public Contact Survey, a supplement to the National Crime Victimization Survey, which collects information from a nationally representative sample of persons in U.S. households on contact with police during a 12-month period.

Washington, DC: U.S. Bureau of Justice Statistics, 2013. 22p.

By Emma Pierson, et al.

To assess racial disparities in police interactions with the public, we compiled and analyzed a dataset detailing over 60 million state patrol stops conducted in 20 U.S. states between 2011 and 2015. We find that black drivers are stopped more often than white drivers relative to their share of the driving-age population, but that Hispanic drivers are stopped less often than whites. Among stopped drivers—and after controlling for age, gender, time, and location— blacks and Hispanics are more likely to be ticketed, searched, and arrested than white drivers. These disparities may reflect differences in driving behavior, and are not necessarily the result of bias. In the case of search decisions, we explicitly test for discrimination by examining both the rate at which drivers are searched and the likelihood searches turn up contraband. We find evidence that the bar for searching black and Hispanic drivers is lower than for searching whites. Finally, we find that legalizing recreational marijuana in Washington and Colorado reduced the total number of searches and misdemeanors for all race groups, though a race gap still persists. We conclude by o↵ering recommendations for improving data collection, analysis, and reporting by law enforcement agencies.

Palo Alto, CA: Stanford University, 2017. 24p.

By Alex Stepick, Steve Held, Cynthia S Hernandez, Cheryl Little and Susana Barciela

This report addresses the impact on Miami-Dade County of the Secure Communities program, currently one of the primary federal immigration enforcement programs administered by the Department of Homeland Security (DHS) through Immigration and Customs Enforcement (ICE). DHS claims that the program prioritizes the removal of convicted criminal aliens who pose a danger to national security or public safety, repeat violators who game the immigration system, those who fail to appear at immigration hearings, and fugitives who have already been ordered removed by an immigration judge.” Contrary to these policy goals, we found that 61% of individuals ordered for removal from Miami-Dade County are either low level offenders or not guilty of the crime for which they were arrested. By ICE’s standards only 18% of the individuals ordered for removal represent high priority public safety risks, and that number drops to a mere 6% when we apply local standards suggested by Miami-Dade County’s Public Defender. Interviews with detainees also reveal that often residents are stopped by police for no apparent reason and subjected to detention and deportation. Secure Communities in Miami-Dade County also has a disproportionately negative impact on Mexicans and Central Americans who constitute a relatively low percentage of the local population but a high percentage of those whom Secure Communities detained and removed.

Miami: Research Institute on Social & Economic Policy Center for Labor Research & Studies Florida International University and Americans for Immigrant Justice, 2013. 57p.

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 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 Fabien Jobard and René Lévy

French residents of immigrant origin, particularly those of North African and sub-Saharan African background, have long complained that police single them out for unfair, discriminatory, and unnecessary identity checks. If these perceptions are true, it means that French police are engaged in “ethnic profiling.” That is, police officers are basing decisions about who may be suspicious on the basis of the color of their skin or their assumed ethnic identity rather than on the basis of their individual behavior. In 2007, the Open Society Justice Initiative launched a study to examine whether and to what extent law enforcement officers stop individuals based on their appearance. This study was conducted in collaboration with Fabien Jobard and René Lévy, researchers with the National Center for Scientific Research (Centre National de la Recherche Scientifique) in France. The study was carried out under the technical supervision of Lamberth Consulting. Examining five locations in and around the Gare du Nord and Châtelet-Les Halles rail stations, all important transit points in central Paris that are also the sites of heavy police activity, Profiling Minorities : A Study of Stop-and-Search Practices in Paris gathered data on police stops carried out by National Police and Customs officers, including information on the ethnicity, age, gender, clothing, and bags carried by the persons who were stopped. This study, which generated unique information on over 500 police stops, is the first to gather the quantitative data necessary to identify and detect patterns of ethnic profiling in France. The study confirmed that police stops and identity checks in Paris are principally based on the appearance of the person stopped, rather than on their behavior or actions. Persons perceived to be ethnic minorities were disproportionately stopped by the police. The results show that persons perceived to be “Black” (of sub-Saharan African or Caribbean origin) and “Arab” (of North African or Maghrebian origin) were stopped at proportionally much higher rates than persons perceived to be “White” (of Western European origin). Across the five observations sites, Blacks were overall six times more likely than Whites to be stopped by police ; the site-specific rates of disproportionality ranged from 3.3 to 11.5. Arabs were generally 7.6 times more likely than Whites to be stopped by the police, although again, the specific rate of disproportionality across the five locations ranged from 1.8 and 14.8. Follow-up interviews with the individuals who were stopped also suggest that these two groups regularly experience far more police stops than Whites.

New York: Open Society Institute, 2019. 82p.