Unusual suspects
Randomized controlled field trials of predictive policing
George Mohler et al.
Journal of the American Statistical Association, forthcoming
Abstract:
The concentration of police resources in stable crime hotspots has proven effective in reducing crime, but the extent to which police can disrupt dynamically changing crime hotspots is unknown. Police must be able to anticipate the future location of dynamic hotspots to disrupt them. Here we report results of two randomized controlled trials of near real-time Epidemic Type Aftershock Sequence (ETAS) crime forecasting, one trial within three divisions of the Los Angeles Police Department and the other trial within two divisions of the Kent Police Department (UK). We investigate the extent to which i) ETAS models of short term crime risk outperform existing best practice of hotspot maps produced by dedicated crime analysts, ii) police officers in the field can dynamically patrol predicted hotspots given limited resources, and iii) crime can be reduced by predictive policing algorithms under realistic law enforcement resource constraints. While previous hotspot policing experiments fix treatment and control hotspots throughout the experimental period, we use a novel experimental design to allow treatment and control hotspots to change dynamically over the course of the experiment. Our results show that ETAS models predict 1.4-2.2 times as much crime compared to a dedicated crime analyst using existing criminal intelligence and hotspot mapping practice. Police patrols using ETAS forecasts led to a average 7.4% reduction in crime volume as a function of patrol time, whereas patrols based upon analyst predictions showed no significant effect. Dynamic police patrol in response to ETAS crime forecasts can disrupt opportunities for crime and lead to real crime reductions.
---------------------
Do Stop, Question, and Frisk Practices Deter Crime? Evidence at Microunits of Space and Time
David Weisburd et al.
Criminology & Public Policy, forthcoming
Abstract:
Existing studies examining the crime impacts of stop, question, and frisks (SQFs) have focused on large geographic areas. Weisburd, Telep, and Lawton (2014) suggested that SQFs in New York City (NYC) were highly concentrated at crime hot spots, implying that a microlevel unit of analysis may be more appropriate. The current study aims to address the limitations of prior studies by exploring the impact of SQFs on daily and weekly crime incidents in NYC at a microgeographic level. The findings suggest that SQFs produce a significant yet modest deterrent effect on crime.
---------------------
Cody Ross
PLoS ONE, November 2015
Abstract:
A geographically-resolved, multi-level Bayesian model is used to analyze the data presented in the U.S. Police-Shooting Database (USPSD) in order to investigate the extent of racial bias in the shooting of American civilians by police officers in recent years. In contrast to previous work that relied on the FBI’s Supplemental Homicide Reports that were constructed from self-reported cases of police-involved homicide, this data set is less likely to be biased by police reporting practices. County-specific relative risk outcomes of being shot by police are estimated as a function of the interaction of: 1) whether suspects/civilians were armed or unarmed, and 2) the race/ethnicity of the suspects/civilians. The results provide evidence of a significant bias in the killing of unarmed black Americans relative to unarmed white Americans, in that the probability of being {black, unarmed, and shot by police} is about 3.49 times the probability of being {white, unarmed, and shot by police} on average. Furthermore, the results of multi-level modeling show that there exists significant heterogeneity across counties in the extent of racial bias in police shootings, with some counties showing relative risk ratios of 20 to 1 or more. Finally, analysis of police shooting data as a function of county-level predictors suggests that racial bias in police shootings is most likely to emerge in police departments in larger metropolitan counties with low median incomes and a sizable portion of black residents, especially when there is high financial inequality in that county. There is no relationship between county-level racial bias in police shootings and crime rates (even race-specific crime rates), meaning that the racial bias observed in police shootings in this data set is not explainable as a response to local-level crime rates.
---------------------
Stereotyping? Evidence from Reactions to Police Deaths
Heather Sarsons
Harvard Working Paper, November 2015
Abstract:
Stereotypes lead people to over-react to information that confirms their priors and under-react to information that goes against their priors. I test a model of stereotyping using data on police officer assaults. I match data from the New York City Stop, Question, and Frisk program to data on police deaths to test whether police officers have different responses to shootings depending on the shooter's race. I find that when an officer is shot by a white civilian, there is no change in frisk, arrest, or use of force patterns. However, when an officer is shot by a black civilian, frisking and use of force against black civilians increases dramatically. I test alternative explanations such as rational updating, retaliation, and demographic segregation.
---------------------
Risk, Race, & Recidivism: Predictive Bias and Disparate Impact
Jennifer Skeem & Christopher Lowenkamp
University of California Working Paper, November 2015
Abstract:
One way to unwind mass incarceration without compromising public safety is to use risk assessment instruments in sentencing and corrections. These instruments figure prominently in current reforms, but controversy has begun to swirl around their use. The principal concern is that benefits in crime control will be offset by costs in social justice — a disparate and adverse effect on racial minorities and the poor. Based on a sample of 34,794 federal offenders, we empirically examine the relationships among race (Black vs. White), actuarial risk assessment (the Post Conviction Risk Assessment [PCRA]), and re-arrest (for any/violent crime). First, application of well-established principles of psychological science revealed no real evidence of test bias for the PCRA — the instrument strongly predicts re-arrest for both Black and White offenders and a given score has essentially the same meaning — i.e., same probability of recidivism — across groups. Second, Black offenders obtain modestly higher average scores on the PCRA than White offenders (d = .43; appx. 27% non-overlap in groups’ scores). So some applications of the PCRA could create disparate impact — which is defined by moral rather than empirical criteria. Third, most (69%) of the racial difference in PCRA scores is attributable to criminal history — which strongly predicts recidivism for both groups and is embedded in sentencing guidelines. Finally, criminal history is not a proxy for race — instead, it fully mediates the otherwise weak relationship between race and re-arrest. Data may be more helpful than rhetoric, if the goal is to improve practice at this opportune moment in history.
---------------------
Andrea Knittel et al.
Social Science & Medicine, forthcoming
Abstract:
Men who have been incarcerated experience substantial changes in their sexual behavior after release from jail and prison, and high rates of incarceration may change sexual relationship patterns at a community level. Few studies, however, address how rates of incarceration affect community patterns of sexual behavior, and the implications of those patterns for HIV and STD risk. We describe a “proof of principle” computational model that tests whether rates of male incarceration could, in part, explain observed population-level differences in patterns of sexual behavior between communities with high rates of incarceration and those without. This validated agent-based model of sexual partnership among 20-25 year old heterosexual urban residents in the United States uses an algorithm that incarcerates male agents and then releases them back into the agent community. The results from these model experiments suggest that at rates of incarceration similar to those observed for urban African American men, incarceration can cause an increase in the number of partners at the community level. The results suggest that reducing incarceration and creating a more open criminal justice system that supports the maintenance of inmates’ relationships to reduce instability of partnerships for men who are incarcerated may have important sexual health and public health implications. Incarceration is one of many social forces that affect sexual decision-making, and incarceration rates may have substantial effects on community-level HIV and STD risks.
---------------------
Justin Ready & Jacob Young
Journal of Experimental Criminology, September 2015, Pages 445-458
Objectives: On-officer video camera (OVC) technology in policing is developing at a rapid pace. Large agencies are beginning to adopt the technology on a limited basis, and a number of cities across the United States have required their police departments to adopt the technology for all first responders. However, researchers have just begun to examine the effects of OVC technology on citizen complaints, officers’ attitudes, and police–citizen contacts.
Methods: This study examines officer behavior and perceptions of camera technology among 100 line officers in the Mesa Police Department during police–citizen encounters over a 10-month period. Experimental data from 3698 field contact reports were analyzed to determine whether being assigned to wear an OVC influences officer behavior and perceptions of OVC technology.
Results: Bivariate and multilevel logistic regression analyses indicate that officers assigned to wear a camera were less likely to perform stop-and-frisks and make arrests, but were more likely to give citations and initiate encounters. Officers were also more likely to report OVCs as being helpful if they wore a camera and in situations where they issued a warning or citation, performed a stop-and-frisk, and made an arrest.
Conclusions: Our results provide important insights into the consequences of OVCs on police behavior and suggest that officers are more proactive with this technology without increasing their use of invasive strategies that may threaten the legitimacy of the organization.
---------------------
Stacey Hust et al.
Journal of Health Communication, December 2015, Pages 1369-1381
Abstract:
Previous research has identified that exposure to the crime drama genre lowers rape myth acceptance and increases sexual assault prevention behaviors such as bystander intervention. However, recent content analyses have revealed marked differences in the portrayal of sexual violence within the top three crime drama franchises. Using a survey of 313 college freshmen, this study explores the influence of exposure to the three most popular crime drama franchises: Law & Order, CSI, and NCIS. Findings indicate that exposure to the Law & Order franchise is associated with decreased rape myth acceptance and increased intentions to adhere to expressions of sexual consent and refuse unwanted sexual activity; whereas exposure to the CSI franchise is associated with decreased intentions to seek consent and decreased intentions to adhere to expressions of sexual consent. Exposure to the NCIS franchise was associated with decreased intentions to refuse unwanted sexual activity. These results indicate that exposure to the specific content of each crime drama franchise may have differential results on sexual consent negotiation behaviors.
---------------------
Charles Manski & John Pepper
NBER Working Paper, November 2015
Abstract:
Despite dozens of studies, research on crime in the United States has struggled to reach consensus about the impact of right-to-carry (RTC) gun laws. Empirical results are highly sensitive to seemingly minor variations in the data and model. How then should research proceed? We think that policy analysis is most useful if researchers perform inference under a spectrum of assumptions of varying identifying power, recognizing the tension between the strength of assumptions and their credibility. With this in mind, we formalize and apply a class of assumptions that flexibly restrict the degree to which policy outcomes may vary across time and space. Our bounded variation assumptions weaken in various respects the invariance assumptions commonly made by researchers who assume that certain features of treatment response are constant across space or time. Using bounded variation assumptions, we present empirical analysis of the effect of RTC laws on violent and property crimes. We allow the effects to vary across crimes, years and states. To keep the analysis manageable, we focus on drawing inferences for three states – Virginia, Maryland, and Illinois. We find there are no simple answers; empirical findings are sensitive to assumptions, and vary over crimes, years, and states. With some assumptions, the data do not reveal whether RTC laws increase or decrease the crime rate. With others, RTC laws are found to increase some crimes, decrease other crimes, and have effects that vary over time for others.
---------------------
A structural analysis of U.S. drunk driving policy
Darren Grant
International Review of Law and Economics, forthcoming
Abstract:
The expected penalty for drunk driving can and does vary by blood alcohol content. This paper outlines the schedule of penalties that best achieves two key social objectives, efficacy and efficiency (subject to constraints), shows how the associated optimality conditions can be implemented with available data to analyze policy ex ante or ex post, and then uses these findings to assess four fundamental features of current U.S. drunk driving policy. Large penalties at very high alcohol concentrations are supported, but not reductions in per se blood alcohol thresholds, the most significant recent change in policy.
---------------------
Minor Physical Anomalies as a Window into the Prenatal Origins of Pedophilia
Fiona Dyshniku et al.
Archives of Sexual Behavior, November 2015, Pages 2151-2159
Abstract:
Evidence is steadily accumulating to support a neurodevelopmental basis for pedophilia. This includes increased incidence of non-right-handedness, which is a result primarily of prenatal neural development and solidified very early in life. Minor physical anomalies (MPAs; superficial deviations from typical morphological development, such as un-detached earlobes) also develop only prenatally, suggesting them as another potential marker of atypical physiological development during the prenatal period among pedophiles. This study administered the Waldrop Physical Anomaly Scale to assess the prevalence of MPAs in a clinical sample of men referred for assessment following a sexual assault, or another illegal or clinically significant sexual behavior. Significant associations emerged between MPA indices and indicators of pedophilia, including penile responses to depictions of children, number of child victims, and possession of child pornography. Moreover, greater sexual attraction to children was associated with an elevated craniofacial-to-peripheral anomalies ratio. The overall sample demonstrated a greater number of MPAs relative to prior samples of individuals with schizophrenia as well as to healthy controls.
---------------------
The Complexity of Hate Crime and Bias Activity: Variation across Contexts and Types of Bias
Andrew Gladfelter, Brendan Lantz & Barry Ruback
Justice Quarterly, forthcoming
Abstract:
Are racially-motivated hate crimes, non-criminal bias incidents, and general forms of crime associated with the same structural factors? If so, then social disorganization, a powerful structural correlate of general crime, should predict rates of hate incidents. However, tests of social disorganization’s effects on racially-motivated hate crime yield inconsistent results. This study uses data from the Pennsylvania Human Relations Commission (PHRC) to explore such inconsistencies. Specifically, we assess the effects of social disorganization across contexts and types of bias motivation using bias incidents over 12 years. The results suggest that (a) social disorganization, particularly residential instability, is robustly correlated with rates of both hate crime and other prejudicial conduct, and that (b) the interactive effects of social disorganization help explain variations in incident rates by motivation type. Specifically, anti-black incidents are most frequent in unstable, homogeneous (i.e. white) and advantaged communities, while anti-white incidents are most frequent in unstable, disadvantaged communities.
---------------------
Michael Ruderman, Deirdra Wilson & Savanna Reid
PLoS ONE, October 2015
Objective: This administrative data-linkage cohort study examines the association between prison crowding and the rate of post-release parole violations in a random sample of prisoners released with parole conditions in California, for an observation period of two years (January 2003 through December 2004).
Methods: Rates of parole violation for parolees exposed to high and medium levels of prison crowding were compared to parolees with low prison crowding exposure. Hazard ratios (HRs) with 95% confidence intervals (CIs) were estimated using a Cox model for recurrent events. Our dataset included 13070 parolees in California, combining individual level parolee data with aggregate level crowding data for multilevel analysis.
Results: Comparing parolees exposed to high crowding with those exposed to low crowding, the effect sizes from greatest to least were absconding violations (HR 3.56 95% CI: 3.05–4.17), drug violations (HR 2.44 95% CI: 2.00–2.98), non-violent violations (HR 2.14 95% CI: 1.73–2.64), violent and serious violations (HR 1.88 95% CI: 1.45–2.43), and technical violations (HR 1.86 95% CI: 1.37–2.53).
Conclusions: Prison crowding predicted higher rates of parole violations after release from prison. The effect was magnitude-dependent and particularly strong for drug charges. Further research into whether adverse prison experiences, such as crowding, are associated with recidivism and drug use in particular may be warranted.
---------------------
Locked and not Loaded: First Time Offenders and State Ignition Interlock Programs
Darin Ullman
International Review of Law and Economics, forthcoming
Abstract:
Alcohol-related fatal crashes are a costly public safety concern. Using vehicular fatality data and geographical variations across the United States, I examine the effectiveness of mandatory Ignition Interlock Programs for first time offenders in preventing fatal alcohol-related accidents. I observe that the program is most effective when it is applied to a broader cross-section of first time offenders. Specifically, states that adopt ignition interlock laws that require participation of first time offenders, with blood alcohol levels of .08 or higher, see fatal accidents involving a drunk driver decrease by 9%. The results provide evidence in support of current and future policy legislation that first time offenders should participate in ignition interlock programs, which will reduce alcohol-related fatal accidents and generate large benefits to society.
---------------------
Under the Cover of Darkness: How Ambient Light Influences Criminal Activity
Jennifer Doleac & Nicholas Sanders
Review of Economics and Statistics, forthcoming
Abstract:
We exploit daylight saving time (DST) as an exogenous shock to daylight, using both the discontinuous nature of the policy and the 2007 extension of DST, to consider the impact of light on criminal activity. Regression discontinuity estimates show a 7% decrease in robberies following the shift to DST. As expected, effects are largest during the hours directly affected by the shift in daylight. We discuss our findings within the context of criminal decision making and labor supply, and estimate that the 2007 DST extension resulted in $59 million in annual social cost savings from avoided robberies.
---------------------
Phillip Marotta
Police Quarterly, December 2015, Pages 414-441
Abstract:
An overwhelming body of literature points to a relationship between experiencing adversity during childhood and later violence in adulthood. This study addresses a gap in existing research by testing of the impact of four prior childhood adversities on resistant behaviors toward law enforcement officers. A four-level ordinal dependent variable measuring passive resistance, verbal resistance, police action resistance, and physical resistance was created using data from the nationally representative, 2004 Survey of Inmates in State and Federal Correctional Facilities. A generalized ordinal logistic regression model tested the effects of childhood adversities on resistant behaviors toward law enforcement officers. Physical victimization during childhood and adulthood predicted resistant behaviors toward law enforcement officers above and beyond the effects of prior victimization during only childhood and only adulthood. This study found a strong association between prior physical victimization, foster care involvement, and resistant behaviors after adjusting for demographic, situational, and criminal background variables.
---------------------
Exploring the sanction–crime relationship through a lens of procedural justice
Megan Bears Augustyn & Jeffrey Ward
Journal of Criminal Justice, November–December 2015, Pages 470–479
Purpose: Research overwhelmingly explores “kinds of people” as moderators of the sanction–crime relationship (Piquero et al., 2011). This work, on the other hand, focuses on the sanction experience and draws upon the procedural justice doctrine and key ideas in Sherman's (1993, 2014) defiance theory to test whether individual evaluations of procedural justice condition the effect of legal sanctions on subsequent criminal behavior.
Methods: Using a sample of serious adolescent offenders, generalized linear regression models with interaction terms are employed to test whether the effect of legal sanctions on involvement, variety, and frequency of offending is conditioned by procedural justice. Significant interaction effects of legal sanction and procedural justice are illustrated with graphical methods.
Results: Results suggest that evaluations of procedural justice condition the sanction–crime relationship. Sanctions lead to a higher likelihood of offending among individuals with low evaluations of procedural justice. However, among those with higher evaluations of procedural justice, there is no significant relationship between sanctions and subsequent offending.
Conclusion: Increasing perceptions of procedural justice reduces unintended consequences of sanctioning experiences. In an era of heightened focus on interactions between citizens and criminal justice professionals, enhancing procedural justice is not only ethical but also protects against deviance amplification processes.
---------------------
Danielle Wallace et al.
Justice Quarterly, forthcoming
Abstract:
Legitimacy-based approaches to crime prevention assume that individuals will comply with the law when they believe that the law and its agents are legitimate and act in ways that are “fair” and “just.” Currently, legitimacy-based programs are shown to lower aggregate levels of crime; yet, no study has investigated whether such programs influence individual offending. Using quasi-experimental design and survival analyses, this study evaluates the effectiveness of one such program — Chicago’s Project Safe Neighborhoods’ (PSN) Offender Notification Forums — at reducing individual recidivism among a population of returning prisoners. Results suggest that involvement in PSN significantly reduces the risk of subsequent incarceration and is associated with significantly longer intervals that offenders remain on the street and out of prison. As the first study to provide individual-level evidence promoting legitimacy-based interventions on patterns of individual offending, out study suggests these interventions can and do reduce rates of recidivism.
---------------------
Jerry Ratcliffe et al.
Journal of Experimental Criminology, September 2015, Pages 393-417
Objectives: We explore whether the use of foot patrol, problem-oriented policing and offender-focused policing at violent crime hot spots negatively impacted the community’s perceptions of crime and disorder, perceived safety, satisfaction with police and their perceptions of procedural justice.
Methods: We report on a repeated cross-sectional survey that was mailed before and after the deployment of concentrated police interventions in 60 small areas of Philadelphia, PA, as part of the Philadelphia Policing Tactics Experiment. Eighty-one violent crime hot spots were randomly allocated to one of three treatments (20 each), or to a control assignment (21). Impacts on the community via seven scales were analyzed using OLS models with orthogonal contrast-coded treatment variables and demographic covariates.
Results: The OLS models estimating changes in the community’s opinions from pre- to post-intervention uncovered no statistically significant changes on any of the dependent variables relative to control locations, irrespective of the treatment type. Even though one experimental treatment condition (offender-focused) reported statistically significant violent crime reductions, the police activity that generated the crime reduction did not noticeably change community perceptions of crime and disorder, perceived safety, satisfaction with police or procedural justice.
Conclusions: As implemented in Philadelphia, none of the policing tactics had measurable changes in resident perception within the communities that were targeted. The results do not support the suggestion that hot spots policing negatively impacts the community. At the same time, no positive benefits were generated.
---------------------
Cross-border homicide impacts on economic activity in El Paso
Pedro Niño et al.
Empirical Economics, December 2015, Pages 1543-1559
Abstract:
Drug-related homicides in Ciudad Juárez drastically increased beginning in 2008. Few studies have been carried out which assess the economic impacts of crime and homicides. Furthermore, the existing literature generally lacks regional assessment efforts. Because of geographical proximity and close economic ties, this paper reviews some of the potential impacts the Ciudad Juárez homicides may have on the El Paso regional economy. A time series data approach is employed to quantify links between organized crime homicides in Ciudad Juárez and economic conditions in El Paso as measured by the metropolitan business cycle index and total nonagricultural employment. Findings indicate that fluctuations in the number of Ciudad Juárez homicides impact both variables in statistically significant manners at multiple time lags.