Increasing underrepresented groups’ representation in police departments is a common proposal to reduce aggressive policing. This paper documents the effects of peer composition in the Chicago police academy on officers’ future arrests by exploiting the lottery system, which provides exogenous variation in cohort composition. I find that higher shares of peers from groups that police less aggressively, such as female and older officers, reduce all officers’ future low-level arrests. Peer race matters by amplifying the effects of gender and age. Overall, the results are most consistent with peers’ preferences for less aggressive policing shifting officers’ preferences and changing future behavior.

Partisans are increasingly divided on policing policy, which may affect officer behavior. We merge rosters from 99 of the 100 largest local U.S. agencies—over one third of local law enforcement nationwide—with voter files to study police partisanship. Police skew more Republican than their jurisdictions, with notable exceptions. Using fine-grained data in Chicago and Houston, we compare behavior by Democratic and Republican officers facing common circumstances. Overall, we find few partisan differences after correcting for multiple comparisons. But consistent with prior work, we find Black officers make fewer stops and arrests in Chicago, and they use force less in both cities. Comparing same-race Democratic and Republican officers, we find only that White Democrats make more violent-crime arrests than White Republicans in Chicago. Our results suggest that despite Republicans’ preference for more punitive law enforcement policy and their overrepresentation in policing, partisan divisions do not translate into detectable differences in on-the-ground enforcement.

Does policing the police increase crime? We avoid simultaneity effects of increased public oversight following an officer-involved shooting scandal by identifying events in Chicago that only impacted officers’ self-monitoring. We estimate crimes’ response to types of over- sight using generalized synthetic control methods. Cautionary notes from the police union, inducing officers to self-monitor, significantly reduced Constitutional violation complaints without increasing crime. In contrast, complaints and crime rise post-scandal. This suggests that higher crime following more oversight results not solely from depolicing but also from civilian behavior simultaneously changing. Our research suggests that proactive accountability improves police resident interactions without increasing crime.

This paper examines the impact of in-group bias on the internal dynamics of a police department. Prior studies have documented racial bias in policing, but little is known about bias against officers due to lack of available data. We construct a novel panel dataset of Chicago Police Department officers with detailed personnel information. Exploiting quasi-random variation in supervisor assignment, we find that white supervisors are less likely to nominate black officers than white or Hispanic officers. There is weaker evidence that male supervisors are less likely to nominate female officers than male officers. We explore several theories of discrimination that can explain our main findings. Requiring interaction between supervisors and officers reduces the minority nomination gap, but white supervisors still exhibit in-group favoritism. Our findings suggest departments should focus on policies that address in-group bias due to its effect on career advancement.

We study the link between police officers' on-duty injuries and their peers' force use using a network of officers who attended the police academy together through a random lottery. On-duty injuries increase the probability of officers using force by 7 percent in the subsequent week. Officers are also more likely to injure suspects and receive complaints about neglecting victims and violating constitutional rights. The effect is concentrated in a narrow time window following the event and is not associated with significantly lower injury risk to the officer. Together, these findings suggest that emotional responses drive the effects rather than social learning.

Diversification is a widely proposed policing reform, but its impact is difficult to assess. We used records of millions of daily patrol assignments, determined through fixed rules and preassigned rotations that mitigate self-selection, to compare the average behavior of officers of different demographic profiles working in comparable conditions. Relative to white officers, Black and Hispanic officers make far fewer stops and arrests, and they use force less often, especially against Black civilians. These effects are largest in majority-Black areas of Chicago and stem from reduced focus on enforcing low-level offenses, with greatest impact on Black civilians. Female officers also use less force than males, a result that holds within all racial groups. These results suggest that diversity reforms can improve police treatment of minority communities.

This paper studies the effect of pretrial electronic monitoring (EM) as an alternative to both pretrial release and pretrial detention (jail) in Cook County, Illinois. EM often involves a defendant wearing an electronic ankle bracelet that tracks their movement and aims to deter pretrial misconduct. Using the quasi-random assignment of bond court judges, I estimate the effect of EM versus release and EM versus detention on pretrial misconduct, case outcomes, and future recidivism. I develop a novel method for the semiparametric estimation of marginal treatment effects in ordered choice environments, with which I construct relevant treatment effects. Relative to release, EM increases new cases pretrial due to bond violations while reducing new cases for low-level crimes and failures to appear in court. Relative to detention, EM increases low-level pretrial misconduct but improves defendant case outcomes and reduces cost-weighted future recidivism. Finally, I bound EM's pretrial crime reduction effect. I find that EM is likely an adequate substitute for pretrial detention. However, it is not clear that EM prevents enough high-cost crime to justify its use relative to release, particularly for defendants who are more likely to be released.

Do investors anticipate that demands for racial equity will impact companies? We explore this question in the context of the Black Lives Matter (BLM) movement---the largest racially motivated protest movement in U.S. history---and its effect on the U.S. policing industry using a novel dataset on publicly traded firms contracting with the police. It is unclear whether the BLM uprisings were likely to increase or decrease market valuations of firms contracting heavily with police because of the increased interest in reforming the police, fears over rising crime, and pushes to "defund the police". We find, in contrast to the predictions of economics experts we surveyed, that in the three weeks following incidents triggering BLM uprisings, policing firms experienced a stock price increase of seven percentage points relative to the stock prices of nonpolicing firms in similar industries. In particular, firms producing surveillance technology and police accountability tools experienced higher returns following BLM activism--related events. Furthermore, policing firms' fundamentals, such as sales, improved after the murder of George Floyd, suggesting that policing firms' future performances bore out investors' positive expectations following incidents triggering BLM uprisings. Our research shows how---despite BLM’s calls to reduce investment in policing and explore alternative public safety approaches---the financial market has translated high-profile violence against Black civilians and calls for systemic change into shareholder gains and additional revenues for police suppliers.

We study how negative sentiment around an industry impacts beliefs and behaviors, focusing on demands for racial justice after the murder of George Floyd and the salience of the “defund the police” movement. We assess stakeholder beliefs on the impact of protests on the stock prices of police-affiliated firms. In our survey experiment, laypeople and finance professionals predicted more negative stock price outcomes when they lacked details on the products supplied by such firms. Exposure to narratives about the context of the protests further reduced the prediction accuracy of these groups. In contrast, product information improved the prediction accuracy of respondents. Turning to real-life behavior, we find that mutual funds exposed to protests were 20% less likely to hold police stocks, after the protests, than funds in areas without protests. Political support for maintaining police funding, though in the majority, declined by 4.3 percentage points in protest areas. The salience of the “defund the police” narrative led to significant overreactions in both financial predictions and real-life behavior.

Theories of crime in economics focus on the roles of deterrence and incapacitation in reducing criminal activity. In addition to deterrence, a growing body of empirical evidence has shown that both income support and employment subsidies can play a role in crime reduction. This paper extends the Becker-Ehrlich model to a standard labor supply model that includes the notion of a consumption need (Barzel and McDonald (1973)) highlights the role of substitution vs income effects when an individual chooses to engage in crime. Second, we show that whether the production of criminal activity is a substitute or a complement with the production of legitimate activity is central to the design of optimal policy. We find that both individual responsiveness to deterrence and optimal policy vary considerably with context, which is consistent with the large variation in the effect of deterrence on crime. Hence, optimal policy is a combination of deterrence, work subsidies and direct income transfers to the individual that vary with both income and location.

We develop an empirical model of the mechanism used to assign police officers to Chicago districts and examine the efficiency and equity of alternative allocations. We document that the current bidding process, which grants priority based on seniority, results in the assignment of more experienced officers to less violent and high-income neighborhoods. Our empirical model combines estimates of heterogeneous officer preferences underlying the bidding process with causal estimates of the effects of officer experience on neighborhood crime.

Equalizing officer seniority across districts would reduce violent crime rate by 4.6 percent and significantly decrease inequality in crime, discretionary arrests, and officer use of force across neighborhoods. Moreover, this assignment can be achieved in a revenue-neutral way while resulting in small welfare gains for police officers, implying that it is more equitable and efficient.