Program Profile: Police Body-Worn Cameras (Boston, Massachusetts)

This involves police officers wearing cameras on their uniforms to improve the civility of their interactions with citizens. The program is rated Effective. There were statistically significant reductions in citizen complaints against police and police use-of-force reports for officers who wore cameras, compared with those who did not, and statistically significant reductions in complaints against control officers in the treatment districts, compared with officers in the untreated districts.

An Effective rating implies that implementing the program is likely to result in the intended outcome(s).

This program's rating is based on evidence that includes at least one high-quality randomized controlled trial.

Program Goals

Police body-worn cameras have been adopted by departments across the country in response to citizen demands for greater accountability and increased transparency of officer actions. In 2016 the Boston, Massachusetts, Police Department implemented a pilot body-worn camera program to inform a larger implementation of the technology on its patrol force. The goal of body-worn cameras is to improve the civility of police–citizen interactions and police officer work activities.

Program Activities/Key Personnel  

The Boston Police Department’s body-worn camera pilot aimed to answer policy questions about how the system would operate when implemented across the department’s 2,100 officers, and to address concerns of officers and the community about the use of the technology (Braga et al. 2018). The department developed and implemented a policy to guide the officers’ use of the body-worn camera technology during the pilot program. These policies included a requirement that officers wearing the cameras notify citizens that the interaction was being video-recorded at the outset of the encounter; guidelines to seek consent from citizens before recording in residences during non-warrant or emergency situations; and detailed guidelines on the occurrences when video-recording was mandatory during policing duties, such as during a) vehicle stops, b) investigative person stops, c) all dispatched calls for service involving contact with civilians, d) initial responses by patrol officers, e) searches of persons incident to arrest, f) canine searches, g) incidents of emergency and pursuit driving, h) when an officer reasonably believes a crowd control incident may result in unlawful activity, and i) any civilian contact that becomes adversarial, including a use-of-force incident. All officers wearing body-worn cameras and all supervisors were required to attend department-approved training on the operation of the system.

The pilot implementation occurred over a 1-year period in 5 of the 11 police districts throughout the city, and with plainclothes officers in the Youth Violence Strike Force who used proactive policing tactics to prevent outbreaks of gang violence (Braga et al. 2018).

Program Theory

Two theoretical perspectives that support the use of police body-worn cameras are deterrence and public self-awareness theories (Ariel, Farrar, and Sutherland 2015). Deterrence theory posits that individuals refrain from committing crimes when they perceive the costs of illegal acts to exceed the benefits of those acts (Zimring and Hawkins 1973). The possibility of police body-worn cameras capturing inappropriate or illegal behaviors on video during encounters may cause a deterrent effect for both officers and citizens, by modifying their perceptions of detection and punishment risks (Ariel et al. 2017), especially if the video is released and “goes viral.” Further, this deterrent effect could generate spillover benefits, even among officers not outfitted with the cameras, by modifying the objective risk of their antisocial or illegal behavior being recorded by another officer and subsequently detected by department supervisors.

Public self-awareness theory suggests that people are more likely to compare their immediate behaviors to established internal social norms, comply with rules, and exhibit socially desirable behavior when they know they are being observed (Duval and Wicklund 1972). Therefore, the presence of body-worn cameras may cause police officers and citizens to compare their behavior to expected social norms and standards and may also spur behaviors such as treating others in respectful and procedurally just ways (Ariel, Farrar, and Sutherland 2015; Demir et al. 2018). Public self-awareness theory also lends support to a spillover benefit of body-worn cameras on officers that do not wear them, suggesting that the presence of cameras may cause other officers to behave in ways consistent with societal norms (that is, “this is how everyone is supposed to act”) [Silver et al. 2017].

Study 1

Braga and colleagues (2020a) conducted a randomized controlled trial to assess the effects of the Boston Police Department?s body-worn camera pilot program on complaints against officers and officer use of force over a 12-month implementation period.

Ten Boston Police Department districts were matched into five pairs based on quantitative analyses of official 2015 police district crime and policing data and 2015 U.S. Census American Community Survey data for the block groups that made up the larger district areas, with variables capturing data on crime, calls for service, arrests, field interrogation observation reports, citizen complaints, number of officers assigned, population demographics, and levels of neighborhood concentrated disadvantage. One district from each matched pair was randomly allocated to the body-worn camera treatment group. In addition, Boston?s Youth Violence Strike Force was assigned nonrandomly to the body-worn camera treatment group.

There were 281 eligible officers who worked the day shift (patrol, 7:30 a.m. to 4:00 p.m.; Youth Violence Strike Force, 8:30 a.m. to 5:00 p.m.) and first half shift (patrol and Youth Violence Strike Force, 4:00 p.m. to 11:45 p.m.), as of Sept. 1, 2016. Excluded were officers who were responsible for administrative duties or who were medically incapacitated, on military leave, or assigned to other responsibilities that did not primarily involve law enforcement work on the street. The 281 eligible officers were allocated randomly to either the treatment or control group within the five treatment districts and Youth Violence Strike Force. The initial randomization was used to divide the officers into two nearly equivalent-sized groups (n = 140 treatment officers and n = 141 control officers); then, 100 officers within the treatment group were assigned randomly to wear body-worn cameras at the outset of the pilot program. The remaining 40 officers in the treatment districts that did not receive body-worn cameras were trained in the policy and operations of the technology and served as alternates to the treatment officers outfitted with cameras as attrition occurred over the intervention period and up through Aug. 31, 2017 (the end of the intervention period). There were no statistically significant differences between officers in the treatment and control groups at baseline.

Information on citizen complaints and officer use-of-force incidents generated by these officers were collected for 3 years before the start of the pilot program (2013?15) through databases maintained by the Boston Police Department?s Bureau of Professional Standards. Intention-to-treat analyses based on the initial random assignment to treatment was used.

The impact of body-worn cameras on treatment officer outcomes, compared with control officer outcomes, was estimated through a difference-in-differences estimator with 12-month pre-intervention and 12-month intervention period observations. This approach estimated the difference in a treatment officer?s post-intervention outcomes at time t compared with their pre-intervention outcomes, relative to the same difference for the control officers. Poisson panel regression models were used to estimate direct-treatment impacts on citizen complaints against police and use-of-force reports. No subgroup analysis was conducted.

Study 2

Braga and colleagues (2020b) used the same study sample from Study 1 (Braga et al. 2020a) and conducted a quasi-experimental design with propensity score matching to examine the spillover effects of the Boston Police Department?s pilot body-worn camera program on officer use-of-force reports and citizen complaints for control officers who were present in the same districts as body-worn camera treatment officers over a 12-month implementation period. The sample came from the five matched pairs of Boston Police Department districts where one district from each pair was allocated randomly to the body-worn camera treatment group and then within those districts officers were allocated randomly to the treatment or control group, as described in Study 1. The Boston Police Department then also provided a database of 311 patrol and Anticrime Unit officers from the control districts who were actively performing policing duties and worked the day and first-half shifts as of Sept. 1, 2016. Propensity score matching was used to develop balanced groups of matched control officers from the treatment districts (who did not wear body-worn cameras but were exposed to other officers wearing them) and matched comparison officers from the control districts (who neither wore body-worn cameras nor were exposed to other officers wearing them). Specifically, a radius matching technique with a caliper = .01 was used. The propensity score matching routine included the following characteristics: age, race, sex, time on the job, shift, plainclothes assignment, mean yearly citizen complaints (2013?15), mean yearly use-of-force incidents (2013?15), mean monthly responses to call events (2015), mean monthly crime incident reports (2015), mean monthly arrests (2015), and mean monthly field interrogation observation reports (2015). After the propensity score matching procedure, there were no statistically significant differences between matched control officers from the treatment districts (n = 133) and the matched comparison officers from the control districts (n = 268). Control officers in treatment districts were 91.4 percent male, 62.1 percent white, an average of 36.67 years old, and with an average of 11.6 years on the job. These officers had an average of 0.21 yearly citizen complaints against them and 0.12 use-of-force reports. Comparison officers from the control districts were 94 percent male, 66 percent white, an average of 39.7 years old, with an average 11.8 years on the job. These officers had an average of 0.18 yearly citizen complaints against them and 0.12 use-of-force reports.

The analytical strategy was the same as described in Study 1 (Braga et al. 2020a). The difference-in-differences panel regression models were used to analyze possible diffusion of body-worn camera treatment impacts on outcomes during the 12-month intervention and 12-month pre-intervention periods for the matched control officers in the treatment districts who experienced varying levels of the intervention through contamination, relative to the matched untreated officers in the control districts that did not have the body-worn camera technology present during the intervention period. No subgroup analysis was conducted.

These sources were used in the development of the program profile:

These sources were used in the development of the program profile:

Following are CrimeSolutions-rated programs that are related to this practice:

Body-Worn Cameras’ Effects on Police Officer Behavior

This practice involves the use of body-worn cameras by law enforcement. The aim of this practice is to record interactions from an officer’s point of view to improve accountability and positively affect police officer behavior. The practice is rated No Effects for its effects on officer use of force, officer injuries, officer-initiated calls for service, traffic stops, field interviews, and arrest incidents.

Evidence Ratings for Outcomes

	Justice Systems or Processes - Use of force
	Crime & Delinquency - Assault on officer/officer injuries/resistance
	Crime & Delinquency - Multiple crime/offense types
	Justice Systems or Processes - Officer-initiated calls for service
	Crime & Delinquency - Traffic stops/traffic tickets
	Justice Systems or Processes - Field interviews/stop and frisk

Why might a practice's outcome ratings differ from the ratings of specific programs encompassed by that practice?