An increasingly popular critique of modern policing questions the basic premise of whether the police prevent crime at all. Indeed, many of these claims mirror the work of the late political scientist David H. Bayley, who in his 1996 book, Police for the Future, wrote: 

The police do not prevent crime. This is one of the best kept secrets of modern life. Experts know it, the police know it, but the public does not know it. Yet the police pretend that they are society’s best defense against crime and continually argue that if they are given more resources, especially personnel, they will be able to protect communities against crime. This is a myth.

In stark contrast, a growing consensus in academic research strongly suggests that law enforcement makes critical contributions to public safety both through their presence and the size of the police force. For example, a systematic 2014 review of the empirical literature on hot-spot policing suggests that these strategies produce modest gains in crime control that often diffuse to areas surrounding the hot spots themselves. A 2011 study examining an increase in policing activity within Central London in response to a terrorist attack found that a 10 percent increase in policing activity resulted in a 3–4 percent decline in total crime. An impressive number of studies employing various methodologies demonstrate that an increase in police force size leads to both reductions in property and violent crime. Furthermore, this work also suggests that investments in police personnel are cost-effective and that many U.S. cities are in fact underpoliced.

A more recent study confirms many of these findings. Based on a sample of 242 large U.S. cities over the span of 38 years, the authors found that the hiring of 10–17 officers results in the abatement of one homicide, on average. Moreover, this reduction in homicide victimization disproportionately benefitted Black Americans—a critical finding given that homicide contributes nearly a full year to the Black-white male life expectancy gap. The study also concluded that increasing police personnel resulted in a simultaneous reduction in both index crime (serious offenses such as aggravated assault and robbery) and index crime arrests. The reduction in index arrests was nearly 4–6 times greater for Black Americans and overwhelmingly driven by declines in arrests for robbery and property-related crime. These results are most likely explained by the deterrent effects of increasing the size of the police force. Given that index crime arrests are often associated with lengthy prison sentences, this evidence suggests, perhaps counterintuitively, that police force expansion can help reduce racial disparities in incarceration.

While the aforementioned research provides considerable evidence on the public safety value of law enforcement, legitimate concerns remain that increased police contact may disproportionately target disadvantaged groups and further strain their relationship with racially minoritized communities. For example, research on hot-spot policing also finds evidence of short-run declines in community perceptions of procedural justice and little impact on public opinions of police legitimacy in the long run. Similarly, the previously referenced study on race and police force size documented that expansions in police personnel also led to a significant increase in low-level “quality-of-life” arrests, with the increase being three times as large for Black Americans. (These disparities are largely driven by arrests for liquor law violations and drug possession.) As noted in a 2015 U.S. Department of Justice report on policing practices in Ferguson, Missouri, low-level arrests can lead to financially debilitating fines and racially disparate contact with the criminal justice system.

Much of the conversation about American policing in recent years has been devoted to debating the racial implications of aggressive order-maintenance strategies. An influential 2007 paper found significant racial disparities in stops among Black and Hispanic New Yorkers even after accounting for precinct-level differences in crime rates. Litigation surrounding the 2013 Floyd et al. v. the City of New York ruling was immediately followed by a sharp reduction in both stops by the NYPD and racial disparities in stops among New Yorkers. These findings are largely consistent with more recent research suggesting that imposing equity in exposure to police contact across racial groups may not necessarily come at the expense of public safety.

A related strand of research questions the public safety value of low-level arrests. Leveraging the fact that arrests decline considerably in the short run after the death of an officer in the line of duty, a recent working paper based on a sample of over 2,000 U.S. municipalities suggests that reductions in enforcement activity did not result in any notable changes in reported crime. Additional work suggests that defendants prosecuted for nonviolent misdemeanors possessed substantially higher risks of future arrest and prosecution, with these effects being largest among first-time defendants. While further research remains necessary in order to properly assess the overall public safety value of low-level arrests, these studies raise important questions regarding the efficacy of these practices and their disparate impact on disadvantaged communities.

Policies supporting an increase in policing presence must also wrestle with the potential that greater police-civilian interactions might result in use-of-force events. The 2020 murder of George Floyd in Minneapolis, Minnesota, has left many Americans asking important questions regarding racial disparities in police use of force. Perceived illegitimacies surrounding police use of force possess important societal costs—including declines in the levels of witness cooperation and community engagement necessary for improving public safety.

All of this serves as a backdrop for the recent upward trends in gun violence throughout the United States. While these trends pale in comparison to the unprecedented crime wave leading into the 1990s, the costs of increased gun violence disproportionately fall upon historically disadvantaged communities. Places such as St. Louis, Missouri, are experiencing an escalation in gun violence not seen since America’s historic crime wave—an escalation that is almost exclusively driven by homicide victimization among young Black men.

How should American cities respond to the increase in gun violence? This question is the subject of fierce debate between those who favor more policing and critics who advocate for alternative policy solutions that do not involve law enforcement. Previous research provides fairly robust evidence that increased policing presence can result in modest crime reduction and play a valuable role in bridging the racial gap in public safety. However, much of this work also suggests that unconstrained order maintenance strategies can be inefficient and exacerbate racial disparities.

One potential path forward involves greater investment in precision policing or the concentration of policing resources on the small number of individuals who are overwhelmingly responsible for violent crime in their neighborhoods. One study evaluating the impact of highly coordinated NYPD “gang takedowns” found that gun violence surrounding New York City public housing communities fell by nearly one-third after these interventions. Recent studies also suggest that diversification of the police force could help bridge the racial gap in both enforcement activity and crime victimization. Social policy interventions outside of law enforcement responses also have an important role to play in improving public safety. There are a number of promising local interventions, ranging from nonprofit formation to youth summer employment. How exactly these interventions scale up and fit within the larger public safety landscape remains a vital question for future research. ◘

Further Reading

John J. Donohue III, Benjamin Ewing, David Peloquin, and Robert J. MacCoun,“Rethinking America’s Illegal Drug Policy,” Controlling Crime: Strategies and Tradeoffs, (University of Chicago Press, 2011).

James Forman Jr., Locking Up Our Own: Crime and Punishment in Black America, (Farrar, Straus and Giroux, 2017).

George Kelling and James Q. Wilson, "Broken Windows," Atlantic Monthly 249, No. 3 (1982): 29-38.

Jill Leovy, Ghettoside: A True Story of Murder in America, (One World, 2015).