Study Reveals Less Policing Results in Less Crime

In the last few decades, proactive policing has become a centerpiece of “new policing” strategies across the globe. The logic, commonly associated with the broader theory of order maintenance policing (OMP; also known as broken windows), is that rather than wait for citizens to report criminal conduct, law enforcement should proactively patrol communities, maintaining order through systematic and aggressive low-level policing. According to proponents, increasing police stops, quality-of-life summonses, and low-level arrests deters more serious criminal activity by signalling that the area is being monitored and that deviance will not be tolerated. As a corollary, following a phenomenon termed the Ferguson effect, disengaging from proactive policing emboldens criminals, precipitating spikes in serious crime.

But while elected officials commonly justify proactive policing by pointing to the enforcement of legal statutes, the strategy’s efficacy continues to be debated. A serious concern is that proactive policing diverts finite resources and attention away from investigative units, including detectives working to track down serial offenders and break up criminal networks. Proactive policing also disrupts communal life, which can drain social control of group-level violence. Citizens are arrested, unauthorized markets are disrupted, and people lose their jobs, all of which create more localized stress on individuals already living on the edge. Such strains are imposed directly through proactive policing, and thus are independent from subsequent judgments of guilt or innocence. Inconsistency in aggressive low-level policing across community groups undermines police legitimacy, which erodes cooperation with law enforcement. The cumulative effect increases ‘legal cynicism’—individual reliance on extra-legal sanctions and informal institutions of violence as a replacement for police. Reflecting these mechanisms, we propose that sharply reducing proactive policing in areas where it had been deployed pervasively may actually improve compliance with legal authority, thereby reducing major crimes.

To assess these claims, our study analyses an aberration in NYPD strategy, in which police sharply limited foot patrols, criminal summonses and low-level arrests in a manner unrelated to the city’s underlying crime rate. In the midst of a political fight between Mayor de Blasio, anti-police brutality protesters and the city’s police unions, the NYPD held a work ‘slowdown’ for approximately seven weeks in late 2014 and early 2015. Within New York City (NYC), the most proximate cause of protests against the NYPD was the strangling death of Eric Garner in Staten Island. While there was considerable fallout from the incident itself, the conflict intensified when a grand jury declined to indict the involved officers on 4 December 2014. Thousands of protesters marched across the Brooklyn Bridge, while others blocked portions of the West Side Highway as well as the Lincoln and Holland tunnels. Then, two weeks after the non-indictment decision, two NYPD officers, Wenjian Liu and Rafael Ramos, were fatally shot by an anti-police extremist. Because they are legally prohibited from striking, NYPD officers coordinated a work-to-rule strike. Officers were ordered to respond to calls only in pairs, leave their squad cars only if they felt compelled, and perform only the most necessary duties. The act was a symbolic show of strength to demonstrate the city’s dependence on the NYPD. Officers continued to respond to community calls for service, but refrained from proactive policing by refusing to get out of their vehicles to issue summonses or arrest people for petit crimes and misdemeanours.

Emblematic of the slowdown’s effects (and the change from proactive to responsive policing), zero summonses were issued for quality-of-life violations on New Year’s Eve 2014, while just the week before, two officers were fatally shot responding to a reported robbery. Eventually, under pressure from the media as well as growing demands for city revenue, Commissioner Bratton conceded to the ‘self-initiated’ slowdown in proactive policing, before publicly ordering his officers to return to work by 16 January.

The change in tactics appears particularly stark when compared with the aggressive strategy of proactive policing the NYPD pursued during the preceding decades. Correspondence between the introduction of proactive policing in New York and the city’s historic drop in major crime has been heralded as prima facie evidence of the strategy’s effectiveness. As a result, cities across the globe adopted the NYPD’s protocols and practices, which suggests not only that proactive policing strategies are presumed to deter major crime in NYC, but also that these policies are widely thought to work in other contexts as well.

If, as would seem to be the case, the slowdown was unrelated to the city’s underlying crime rate, this makes for a unique natural experiment to identify the causal effects of changing police practices. While Garner was being arrested for a misdemeanor offense, and the killings of Liu and Ramos were homicides, these three crimes neither reflect nor predict citywide (nor precinct-wide) crime. And while anti-police brutality protests and the ensuing political conflict were tied to policing practices across the country, it is difficult to argue that the protests were caused by NYC’s crime rate.

To assess the slowdown’s effects, we filed a series of Freedom of Information requests soliciting a comprehensive set of NYPD CompStat reports from 2013–2016 (see Supplementary Fig. 1 for an example). CompStat (short for computer statistics) was introduced in New York as part of a series of reforms to target proactive policing at ‘hotspots’ in which crime was most concentrated. The reports document weekly activity in each NYPD precinct. On the basis of findings from earlier research, we are confident that CompStat data represent the best available source of disaggregated information on police behavior and crime, and correlate strongly with the underlying reality (see further discussion in the Methods section). Perhaps the best evidence of their validity comes from the fact that the NYPD uses CompStat reports to allocate police resources and develop strategy in real time.

Examining citywide time series, we find evidence of the timing of the NYPD slowdown, as well as preliminary indications of its effects (Fig. 1). Several policing measures are considered. “Criminal summonses” are charges issued for summary Penal Law Violations (that is, quality-of-life violations, including, most commonly, public consumption of alcohol and disorderly conduct, but not ticketable parking fines or moving violations). “Stop, question and frisks” (SQFs) are temporary street detentions and searches of individuals for contraband. Use of SQFs dropped precipitously to a new baseline in anticipation of the judgment in Floyd versus City of New York, which ordered a series of reforms to prevent unconstitutional racial profiling. “Non-major crime arrests” are arrests for all crimes and misdemeanors, excluding the NYPD’s “seven major crimes”—murder, rape, robbery, felony assault, burglary, grand larceny and grand theft auto. It includes arrests made by members of the precinct as well as officers from the Transit and Housing Departments and two specialized bureaus: the Organized Crime Control Bureau (OCCB) and the Detective Bureau. According to annual NYPD statistics, misdemeanor arrests represented 92% of all non-major crime arrests in 2014.