Kevin Lewis

September 16, 2022

Comparing and Contrasting Rates of Firearm Homicides and Suicides

Rachel Christine Zambrano et al.
Evolutionary Psychological Science, September 2022, Pages 262–278


The present research investigates relations among social-biogeographic factors (i.e., temperature, parasite burden, poverty rate, firearm possession rate, psychopathology rate, and estimated IQ), firearm homicide rate, and firearm suicide rate in each of the 50 states of the United States of America. Analysis of archival state-level data showed that local parasite burden strongly and positively predicted firearm homicide rate (sR = .58, p = < .0001). In contrast, both firearms possession rate (sR = −.18, p = .008) and State psychopathology rate (sR = −.34, p = < .0001) negatively predicted firearm homicide rate. In contrast, State psychopathology rate alone positively predicted suicide rate (sR = .42, p = < .0001). These results, which we discuss in terms of Thornhill’s and Fincher’s Parasite-Stress Model (2011), can be used to provide behavior-driven alternative models of behavior to guide political policy making and therapeutic interventions.

Preferences for Firearms and Their Implications for Regulation
Sarah Moshary, Bradley Shapiro & Sara Drango
University of Chicago Working Paper, August 2022


This paper estimates consumer demand for firearms with the aim of evaluating the likely impacts of firearm regulations. We first conduct a stated-choice-based conjoint analysis and estimate an individual-level demand model for firearms. We validate our estimates using aggregate moments from observational data. Next, we use our estimates to simulate changes in the number and types of guns in circulation under alternative regulations. Importantly, we find that bans or restrictions that specifically target 'assault weapons' increase demand for handguns, which are associated with the vast majority of firearm-related violence. We provide distributions of consumer surplus under counterfactuals and discuss how those distributions could be useful for crafting policy.

‘Driving while black’ (or female) as a function of policing while white (or male)
Michael Heise
Criminal Justice Studies, forthcoming


Existing research on distributional concerns arising out of the police-initiated traffic stop context and its outcomes typically focuses on drivers’ race and gender. Broadening this research focus permits more granular analyses of how key police officer and driver pairings interact. Emerging research implies that if Black and non-white drivers are disadvantaged in traffic stop outcomes owing to racial animus, this disadvantage should be especially acute when the police officer is white. Likewise, if gender stereotypes contribute an advantage to female drivers, this advantage should be particularly evident when the officer is male. To assess these hypotheses, this study analyzes data from the 2015 Police-Public Contact Survey (‘PPCS’) and estimates logit models to examine the impact of key police officer and driver race and gender pairings on police-initiated traffic stop outcomes. Despite focusing on police/driver race and gender pairings where expectations for evidence of systematic bias are at their highest, results from this study indicate that none of the three pairings achieves statistical significance. The findings emphasize that prevailing conventional wisdoms regarding key police/driver race and gender pairings in the police-initiated traffic stop context do not find direct empirical support from the null results in this study.

Internet Governance Through Site Shutdowns: The Impact of Shutting Down Two Major Commercial Sex Advertising Sites
Helen Shuxuan Zeng, Brett Danaher & Michael Smith
Management Science, forthcoming


In the two weeks after the U.S. Congress passed a package of anti-sex trafficking bills on March 21, 2018, two of the largest online commercial sex advertising platforms ceased operation. On March 23, Craigslist voluntarily removed their personals section, which had been dominated by advertisements for commercial sex. And on April 6, the Department of Justice seized, the largest online platform for commercial sex advertisements. Our research examines the impact of these shutdowns on a variety of important outcome variables, notably prostitution arrests and violence against women—variables that the prior literature has shown were impacted by the introduction of commercial sex advertising platforms. We employ a generalized difference-in-differences model by exploiting cross-city variation in the preshutdown usage of the two shuttered sites. We find no causal effect of the shutdowns on any of the outcome variables we measure. Further analysis suggests that these null results are likely due to the fluidity of online markets. Our data show that the majority of advertisers and users of Backpage and Craigslist’s personals quickly moved to other (often off-shore) commercial sex advertising portals. Our results highlight the challenges that governments face in reducing online sex trafficking, as the market for commercial sex advertising appears agile enough to quickly disperse to offshore sites after a few popular domestic sites are shut down. Our results have general implications for the governance of other illegal activities online.

Effects of Automatic Criminal Record Expungements on Employment
Caglar Onal
University of Wisconsin Working Paper, July 2022


Several states have enacted broad automatic expungement laws, such as Clean Slate and expungement for cannabis-related offenses, that destroyed millions of criminal records. Advocates of the automatic expungement laws propose that removing criminal record information might help people with records to improve their economic outcomes by removing barriers to employment. However, this policy might have adverse effects on disadvantaged demographic groups. When risk-averse employers realize that there are many people in the labor market whose criminal background cannot be observed because of automatic expungement, they might hesitate to hire job applicants from demographic groups that are likely to include the majority of ex-offenders, particularly black people with no sort of college education. I test this hypothesis by exploiting the adoption and timing variation of the automatic expungement policies across states. I apply the difference-in-differences and event-study approaches as my identification strategies using individual-level monthly CPS (Current Population Survey) data. The results show that the automatic expungement laws decrease the probability of employment by 3.99 percentage points (-7.79%) for low-educated black people. The magnitude of the effect is higher when I restrict the sample to young black individuals with no high school diploma. Their probability of employment is reduced by 10.8 percentage points (-27.69%).

@#%$!: The Impact of Officer Profanity on Civilians’ Perception of What Constitutes Reasonable Use of Force
Hunter Martaindale et al.
Police Quarterly, forthcoming


The current study was conducted to test how the presence of profane officer language during a use of force incident impacts how civilians perceive the reasonableness of the applied force. The study followed a 1 × 4 independent groups design with random assignment to one of four test conditions. Two dashcam use of force videos were stripped of audio and subsequently transcribed with a clean and profane-laden depiction of the officer’s language. Participants (n = 234) answered a short questionnaire after watching their randomly assigned video. Measures include a 5-item reasonableness index, demographics, and test conditions. Two-way ANOVA and OLS regression were performed. Overall, participants considered videos with profane language to be less reasonable than the same video with clean language. While significant, most differences also correspond with medium and large effect sizes. This research found that profane officer language impacts how civilians perceive force reasonableness. Practical and policy implications are presented to move policing forward.

An Examination of Professional/Trade Law Enforcement Publication Consumption and Sensitivity to the Ferguson Effect Among US Police Chiefs
John Shjarback
Journal of Police and Criminal Psychology, September 2022, Pages 669–680


Empirical research has found that the rise in national attention and criticism toward American law enforcement in the wake of Ferguson (i.e., summer 2014 and beyond) has negatively influenced police officers’ perceptions and behavior. Yet, there is variation in how officers have viewed motivation, morale, and proactivity in the post-Ferguson era. Building on previous work and integrating the “media effects” literatures from the disciplines of political science and communications, specifically Gerbner and colleagues’ cultivation theory, the current study examined whether consulting professional/trade publications was associated with officer perceptions of the Ferguson effect among a nationally representative sample of 163 US police chiefs. Results found that those chiefs who subscribe to/regularly visit professional/trade law enforcement publications, such as Law Enforcement Today and Police1, were more likely to hold negative perceptions of the Ferguson effect. That is, chiefs indicated greater problems with motivation, morale, and productivity in their respective departments. Chiefs who experienced backlash (e.g., protests/demonstrations) in their jurisdictions were also more likely to hold negative perceptions.

Event-level prediction of urban crime reveals a signature of enforcement bias in US cities
Victor Rotaru et al.
Nature Human Behaviour, August 2022, Pages 1056–1068


Policing efforts to thwart crime typically rely on criminal infraction reports, which implicitly manifest a complex relationship between crime, policing and society. As a result, crime prediction and predictive policing have stirred controversy, with the latest artificial intelligence-based algorithms producing limited insight into the social system of crime. Here we show that, while predictive models may enhance state power through criminal surveillance, they also enable surveillance of the state by tracing systemic biases in crime enforcement. We introduce a stochastic inference algorithm that forecasts crime by learning spatio-temporal dependencies from event reports, with a mean area under the receiver operating characteristic curve of ~90% in Chicago for crimes predicted per week within ~1,000 ft. Such predictions enable us to study perturbations of crime patterns that suggest that the response to increased crime is biased by neighbourhood socio-economic status, draining policy resources from socio-economically disadvantaged areas, as demonstrated in eight major US cities.

An audit experiment to investigate the “war on cops”: A research note
David Kirk & Marti Rovira
Journal of Experimental Criminology, September 2022, Pages 569–580

Methods: We conduct an experimental audit study, both before and after heightened unrest from police violence. For service-related job openings, we compare the likelihood of getting an affirmative response from a prospective employer to a job application from a fictitious former police officer (the treatment condition) to the response to one of two control conditions: a former firefighter or a former code enforcement officer.

Results: We do not find evidence that former police officers are discriminated against in the labor market. This finding holds in periods characterized by relatively little social unrest due to police violence as well as periods of heightened protest activity.

The Boys in Blue Are Watching You: The Shifting Metropolitan Landscape and Big Data Police Surveillance in the United States
Scott Duxbury & Nafeesa Andrabi
Social Problems, forthcoming


Despite decades of crime decline, police surveillance has continued to expand through a range of tactics oriented towards policing social disadvantage. Yet, despite attention to the linkages between residential inequality and policing, few studies have accounted for two intertwined structural developments since the turn of the 21st century: (1) the shift away from spatially concentrated patterns of racial segregation within urban centers towards sprawling patterns of economic segregation and (2) the turn from reactive policing towards proactive surveillance. Using the case of big data policing, we create a new measure of big data surveillance in metropolitan areas to examine how changes in segregation have affected the expansion of proactive police surveillance. In contrast to theoretical accounts emphasizing the role of police surveillance in governing economic inequality and perpetuating racial segregation, we do not find evidence that racial segregation or income inequality increase big data surveillance. Instead, much of the recent rise in big data policing is explained by increases in sprawling patterns of income segregation. These results provide new insight into the linkages between policing and residential inequality and reveal how changes in metropolitan segregation influence criminal justice surveillance in the era of big data.

Race, work history, and the employment recidivism relationship
Simon Kolbeck, Paul Bellair & Steven Lopez
Criminology, forthcoming


Recent studies have found that race, work history, postprison employment, and recidivism are intertwined, suggesting that race and work history may shape the employment–recidivism relationship in nuanced, yet underexplored ways. Additionally, the literature has yet to settle on what kinds of employment patterns matter most for recidivism. These issues are especially important to resolve given contemporary concerns about mass incarceration and racial disparities among citizens returning from prison. To investigate these questions, we analyze administrative prison records, unemployment insurance (UI) quarterly data, and a recidivism follow-up documenting multiple failures for approximately eight years. Frailty models, which address unobserved heterogeneity among those prone to multiple recidivism events, reveal that establishing a recent work history unlocks the protective effect of employment, and that the relationship between postprison employment and recidivism does not vary by race. We also find that being sporadically employed is as protective as being more consistently employed. Our findings imply that employment contributes to racial disparities in recidivism via racialized barriers to labor market participation rather than via differential effects. Our results further suggest that addressing barriers to employment, especially for those with no work history and those facing racialized barriers to labor market entry, could significantly reduce recidivism.

Law Enforcement Agencies’ College Education Hiring Requirements and Racial Differences in Police-Related Fatalities
Thaddeus Johnson et al.
Journal of Police and Criminal Psychology, September 2022, Pages 681–698


This study examines the effects of agency education requirements on racial differences in police-related fatalities (PRFs) across 235 large US cities between 2000 and 2016. We estimated Poisson pseudo-maximum likelihood (PPML) regression models with multiple fixed effects using data from the Fatal Encounters database, Bureau of Justice Statistics’ Law Enforcement Management and Administrative Statistics survey, and other publicly available databases. Results show that adopting agency college degree requirements is generally associated with decreases in PRFs over time, with significant reductions observed for PRFs of Black and unarmed citizens. Our study suggests mandating at least an associate’s degree for entry-level officers should equate to lower rates of Black people and unarmed persons killed by police actions and more balance in the racial distribution of PRFs. Police leaders and local governments should consider these findings when crafting policies to protect against fatal police-citizen encounters.



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