Barak Ariel

Wearing body cameras increases assaults against officers and does not reduce police use of force: Results from a global multi-site experiment

Police use of force is at the forefront of public awareness in many countries. Body-worn videos (BWVs) have been proposed as a new way of reducing police use of force, as well as assaults against officers. To date, only a handful of peer-reviewed randomised trials have looked at the effectiveness of BWVs, primarily focusing on use of force and complaints. We sought to replicate these studies, adding assaults against police officers as an additional outcome. Using a prospective meta-analysis of multi-site, multi-national randomised controlled trials from 10 discrete tests with a total population of +2 million, and 2.2 million police officer-hours, we assess the effect of BWVs on the rates of (i) police use of force and (ii) assaults against officers. Averaged over 10 trials, BWVs had no effect on police use of force (d = 0.021; SE = 0.056; 95% CI: –0.089–0.130), but led to an increased rate of assaults against officers wearing cameras (d = 0.176; SE = 0.058; 95% CI: 0.061–0.290). As there is evidence that cameras may increase the risk of assaults against officers, more attention should be paid to how these devices are implemented. Likewise, since other public-facing organisations are considering equipping their staff with BWVs (e.g. firefighters, private security, traffic wardens), the findings on risks associated with BWVs are transferrable to those occupations as well.

An Integrated Theory of Hot Spots Patrol Strategy: Implementing Prevention by Scaling Up and Feeding Back

In late 2013, Trinidad and Tobago Police Service (TTPS) conducted the first randomized experiment ever to test a hot spots patrol strategy (HSPS) across large areas, as distinct from testing extra patrols one hot spot at a time. The HSPS experiment required, and helped to refine, a formal theory of both the causes and effects of directed patrols in hot spots. This article presents an integrated theory of how to implement an HSPS in ways that maximize the preventive effects of patrol on crime. It then describes the HSPS experimental protocol used to test the theory in Trinidad. The key elements of HSPS are scaling up from specific hot spot locations to a district-wide focus on all its hot spots and feeding back to the constables who provide hot spots patrols data on what they have done and with what effect—presented every 2 weeks, at a district-level “COP-stat” meeting with the people actually doing the patrols.

Title Restorative Justice Conferencing (RJC) Using Face-to-Face Meetings of Offenders and Victims: Effects on Offender Recidivism and Victim Satisfaction. A Systematic Review.

This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.[delete if co-registered] Contributions Heather Strang and Lawrence W. Sherman contributed to the writing and revising of this Review. Daniel J. Woods and Barak Ariel contributed to the statistical analysis. The search strategy was carried out by Evan Mayo-Wilson. Heather Strang will be responsible for updating this review as additional evidence accumulates and as funding becomes available. Potential conflicts of interest The authors have no monetary interest in the results of the review. None of the authors has conducted or published studies that would lead them to slant the evidence on restorative justice in a particular direction. The two senior authors have published studies showing restorative justice both increases crime and reduces it. The Campbell Collaboration (C2) was founded on the principle that systematic reviews on the effects of interventions will inform and help improve policy and services. C2 offers editorial and methodological support to review authors throughout the process of producing a systematic review. A number of C2s editors, librarians, methodologists and external peer-reviewers contribute.

“Contagious Accountability” A Global Multisite Randomized Controlled Trial on the Effect of Police Body-Worn Cameras on Citizens’ Complaints Against the Police

The use of body-worn cameras (BWCs) by the police is rising. One proposed effect of BWCs is reducing complaints against police, which assumes that BWCs reduce officer noncompliance with procedures, improve suspects’ demeanor, or both, leading to fewer complaints. We report results from a global, multisite randomized controlled trial on whether BWC use reduces citizens’ complaints. Seven discrete tests (N = 1,847 officers), with police shifts as the unit of analysis (N = 4,264), were randomly assigned into treatment and control conditions. Using a prospective meta-analytic approach, we found a 93% before–after reduction in complaint incidence (Z = −3.234; p < .001), but no significant differences between trial arms in the studies (d = .053, SE = .11; 95% confidence interval [CI] = [−.163, .269]), and little between-site variation (Q = 4.905; p = .428). We discuss these results in terms of an “observer effect” that influences both officers’ and citizens’ behavior and assess what we interpret as treatment diffusion between experimental and control conditions within the framework of “contagious accountability.”

Randomized Block Designs

Simple random allocation designs in RCTs cannot always guarantee balance in terms of variance, between-group size, or covariant effects. This is particularly the case in smaller trials of a few hundred units or less. These imbalances pose threats to the power of statistical tests, as well as to the precision of treatment estimates. By sacrificing complete randomization in the allocation of treatment(s) of experimental and control units, randomized block designs (RBD) can decrease such threats. Specifically, RBDs, where units are assigned to conditions within homogenized blocks based on a grouping criterion, are commonly employed in other disciplines. We therefore discuss these designs and their advantages for experimental criminology, whose experience with RBDs is fairly limited. Four types of RBDs are presented: the complete blocked randomization-, with and without an interaction term between the treatment and blocking factors, the balanced incomplete block randomization-, and the permuted-blocks randomization-designs. Each is a better fit for certain conditions that arise from the type of data analyzed. We discuss these designs, by showing why, as well as how, each can be implemented in criminology.

Increasing Cooperation With the Police Using Body Worn Cameras

What can change the willingness of people to report crimes? A 6-month study in Denver investigated whether Body Worn Cameras (BWCs) can change crime-reporting behavior, with treatment-officers wearing BWCs patrolling targeted street segments, while control officers patrolled the no-treatment areas without BWCs. Stratified street segments crime densities were used as the units of analysis, in order to measure the effect on the number of emergency calls in target versus control street segments. Repeated measures ANOVAs and subgroup analyses suggest that BWCs lead to greater willingness to report crimes to the police in low crime density level residential street segments, but no discernable differences emerge in hotspot street segments. Variations in reporting are interpreted in terms of accountability, legitimacy, or perceived utility caused by the use of BWCs. Situational characteristics of the street segments explain why low-level street segments are affected by BWCs, while in hotspots no effect was detected.

External validation of the Cardiff model of information sharing to reduce community violence: natural experiment

Background Community violence is a substantial problem for the NHS. Information sharing of emergency department data with community safety partnerships (CSP) has been associated with substantial reductions in assault attendances in emergency departments supported by academic institutions. We sought to validate these findings in a setting not supported by a public health or academic structure. Methods We instituted anonymous data sharing with the police to reduce community violence, and increased involvement with the local CSP. We measured the effectiveness of this approach with routinely collected data at the emergency department and the police. We used police data from 2009, and emergency department data from 2000. Results Initially, the number of assault patients requiring emergency department treatment rose after we initiated data sharing. After improving the data flows, the number of assault patients fell back to the predata-sharing level. There was no change in the number of hospital admissions during the study period. There were decreases in the numbers of violent crimes against the person, with and without injury, recorded by the police. Conclusions We have successfully implemented data sharing in our institution without the support of an academic institution. This has been associated with reductions in violent crime, but it is not clear whether this association is causal.

Can routinely collected ambulance data about assaults contribute to reduction in community violence

Background The ‘law of spatiotemporal concentrations of events’ introduced major preventative shifts in policing communities. ‘Hotspots’ are at the forefront of these developments yet somewhat understudied in emergency medicine. Furthermore, little is known about interagency ‘data-crossover’, despite some developments through the Cardiff Model. Can police-ED interagency data-sharing be used to reduce community-violence using a hotspots methodology? Methods 12-month (2012) descriptive study and analysis of spatiotemporal clusters of police and emergency calls for service using hotspots methodology and assessing the degree of incident overlap. 3775 violent crime incidents and 775 assault incidents analysed using spatiotemporal clustering with k-means++ algorithm and Spearmans rho. Results Spatiotemporal location of calls for services to the police and the ambulance service are equally highly concentrated in a small number of geographical areas, primarily within intra-agency hotspots (33% and 53%, respectively) but across agencies’ hotspots as well (25% and 15%, respectively). Datasets are statistically correlated with one another at the 0.57 and 0.34 levels, with 50% overlap when adjusted for the number of hotspots. At least one in every two police hotspots does not have an ambulance hotspot overlapping with it, suggesting half of assault spatiotemporal concentrations are unknown to the police. Data further suggest that more severely injured patients, as estimated by transfer to hospital, tend to be injured in the places with the highest number of police-recorded crimes. Conclusions A hotspots approach to sharing data circumvents the problem of disclosing person-identifiable data between different agencies. Practically, at least half of ambulance hotspots are unknown to the police; if causal, it suggests that data sharing leads to both reduced community violence by way of prevention (such as through anticipatory patrols or problem-oriented policing), particularly of more severe assaults, and improved efficiency of resource deployment.

Testing the effects of police body-worn cameras on use of force during arrests: A randomised controlled trial in a large British police force:

This study aims to assess the effect of body-worn cameras (BWCs) on police use of force, in a British police force context. We tested the effect of BWCs with a large British force in a six-month ra...

The effects of body-worn cameras (BWCs) on police and citizen outcomes: A state-of-the-art review

Purpose The purpose of this paper is to review the extant of the published literature on body-worn cameras (BWCs) in policing, specifically in the context of how BWCs affect both citizens and officers. Design/methodology/approach The current study is a narrative review of the impact of BWCs on police and citizens generated through a search of four repositories (Google Scholar, Criminal Justice Abstracts, EBSCO Host, PsychInfo). Findings The current narrative review identified 21 articles that matched the selection criteria. In general, this body of research demonstrates that: the police are supportive of BWC adoption; the evidence from BWC evaluations suggests that the use of BWCs can have benefits for police-public encounters. Practical implications The practical implications derived from this narrative review suggest police administrators that the adoption and effective implementation of BWCs are one mechanism that can strengthen police-community relationships and decrease police misconduct through enhanced legitimacy and accountability. Originality/value This study is useful for researchers who wish to further examine BWC issues in policing, for police managers/administrators who are currently utilizing BWC technology, and for those who are considering adopting BWC technology.