Abstract
Objectives
Existing research on the effects of body-worn cameras (BWCs) have found largely consistent results regarding direct significant reductions in citizen complaints and often also report reductions in use of force reports. However, few studies have examined possible spillover effects onto untreated officers. This study explicitly tests for direct and spillover effects of BWCs on the civility of police-citizen encounters and police work activities.
Methods
This study assesses the direct effects of BWCs on citizen complaints, police use of force, and police proactivity and discretion during a 1-year randomized controlled trial in the Boston Police Department. Through a simultaneous quasi-experimental design, this study also investigates whether BWC deployment results in spillover effects onto control officers in treated districts as compared to comparison officers in untreated districts.
Results
Findings indicate that the use of BWCs reduces citizen complaints and police use of force but has no appreciable impact on officer activity or discretion. Furthermore, results indicate significant spillover reductions in citizen complaints for control officers in treated districts.
Conclusions
The results of this study suggest that a limited BWC adoption may generate spillover deterrent impacts as officers and citizens perceive an increased threat that inappropriate and illegal behaviors will be captured on video even when BWCs are not actually present during an encounter. Partial BWC implementation seems like a cost-effective alternative to full implementation. However, police executives and policy makers need to think carefully about possible negative externalities generated by uneven BWC coverage.
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Notes
General-purpose law enforcement agencies include municipal, county, and regional police departments; sheriffs’ offices with law enforcement duties; and primary state and highway patrol agencies (Hyland 2018).
It is worth noting here that it remains unclear whether observed reductions in citizen complaints reflect actual changes in the civility of police-citizen encounters. Complaint reductions may also reflect changes in citizen reporting behaviors driven by a decreased propensity to file frivolous complaints against officers (see Lum et al. 2019 for a discussion).
https://www.bwcscorecard.org/static/policies/2016-07-12%20Boston%20-%20BWC%20Policy.pdf (Accessed November 21, 2018).
Since there was an odd number of policing districts, one district would necessarily be excluded from the matched pairs. BPD District C-6 (South Boston) was not included in the matching process because it was not a good match for the other districts. This was primarily due to the unique presence of a majority white population with higher levels of concentrated disadvantage. It is also important to note here that District A-15 (Charlestown) is a subcommand of District A-1 (Downtown) and not a stand-alone BPD policing district. As such, District A-15 was not included in the matching exercise as there is no other similar subcommand in Boston.
The non-random selection of the YVSF stemmed from two complementary interests. First, the BPD wanted to develop policy and programmatic information on the issues involved in assigning cameras to plainclothes officers relative to uniformed officers. Second, during conversations with community groups on the BWC implementation, community leaders generally recognized YVSF as a key BPD unit engaged in proactive policing activities centered on youth living in disadvantaged minority neighborhoods. These leaders requested that YVSF officers also wear BWCs during the pilot program.
It is possible that BWC officers served as back-up to control officers and did not report their presence to the BPD dispatcher. Given limited funds, we were not able to conduct a field test of this hidden source of contamination that was not captured in the call data. As such, our analyses might be biased to an unknown degree by any BWC officers who did not notify their presence to the dispatcher when backing up control officers during the intervention period.
An index measuring concentrated social disadvantage was calculated by standardizing and summing the following block-group level variables from the 2015 ACS: the percentage of families below the poverty level; percentage of households receiving public assistance; percentage of female-headed households with children; and percentage of the population unemployed.
The 5 control districts were A-1 (Downtown), A-7 (East Boston), C-11 (Dorchester), E-13 (Jamaica Plain), and E-5 (West Roxbury). The 5 treatment districts were B-2 (Roxbury), B-3 (Mattapan), D-4 (Back Bay/South End), D-14 (Allston/Brighton), and E-18 (Hyde Park).
Districts B-2 and B-3 have majority black residential populations (45.3% and 79.5%, respectively). Fagan et al. (2016) found a strong association between the percentage of black residents and the number of FIO encounters reported by the BPD in Boston neighborhoods, controlling for crime and other factors. Two sample t tests of means and two sample z tests of proportions were performed on the matching covariates reported in Table 3. None of the differences reported between the treatment and control districts were statistically significant at the p < .05 level (e.g., percent black residents = -20.8% difference, z = .74, p = .459). Given the small numbers of districts in the two samples (n1 = 5, n2 = 5), the two sample tests were not adequately powered to detect bona fide differences. As such, the results of these hypothesis tests were not robust enough to be reported here.
ACU plainclothes officers assigned to the control districts were included as counterfactuals for the YVSF officers in the control group. ACU officers work to apprehend repeat offenders and increase police presence in crime hot spots within districts. While the foci of ACU activities are broader, the ACU and YVSF engage in similar proactive policing tactics. The matching exercise included n = 38 eligible ACU officers.
Post-estimation likelihood ratio tests confirmed that these outcomes were distributed as Poisson rather than negative binomial processes. For the citizen complaints model, the likelihood χ2 (df = 1) = .78, p = .188. For the officer use of force reports model, the likelihood χ2 (df = 1) = 1.75, p = .093.
These intervention period differences are slightly larger than what was reported in an unpublished preliminary impact evaluation report (see Braga et al. 2018a). The discrepancy is due to a reporting lag in the entry of complaints and use of force reports into the data systems maintained by the BPD Bureau of Professional Standards when the preliminary data were provided to the research team in September 2017. There are no time constraints limiting when complainants can file Internal Affairs Division complaints against BPD officers. Officer use of force reports are investigated and reviewed by an established chain of command.
Note that the program impacts were robust across a variety of matching algorithms and caliper/bandwidth selections: radius matching (caliper .1, .01); Gaussian kernel matching (bandwidth = .01, .001), Epanechnikov kernel matching (bandwidth = .1, .01), and simple nearest neighbor matching. Although the estimates differed slightly across the varying propensity score matching methods, the BWC treatment statistically-significant spillover effect on officer complaints remained robust while the spillover effect on officer use of force reports never reached the less restrictive p < .10 level of significance.
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Acknowledgements
This work was supported through research funds provided by the City of Boston and the Rappaport Institute for Greater Boston. The authors would like to thank Mayor Martin Walsh, Police Commissioner William Evans, Superintendent Kevin Buckley, Superintendent Frank Mancini, Superintendent John Daley, Amy Condon, Desiree Dusseault, and Dawn Mello for their support and assistance in the completion of this research report. The conclusions presented here are those of the authors and do not represent the official position of the City of Boston, Boston Police Department, or the Rappaport Institute for Greater Boston.
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Braga, A.A., Barao, L.M., Zimmerman, G.M. et al. Measuring the Direct and Spillover Effects of Body Worn Cameras on the Civility of Police–Citizen Encounters and Police Work Activities. J Quant Criminol 36, 851–876 (2020). https://doi.org/10.1007/s10940-019-09434-9
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DOI: https://doi.org/10.1007/s10940-019-09434-9