Research

Although empirical research on the outcomes of the use of body-worn cameras (BWC) has been limited to reduction in the number of community member complaints, correlations have been seen between the use of BWCs and reductions in officer use-of-force incidents. In the United Kingdom, Inspector Steve Goodier of the Hampshire Constabulary says that the extended use of BWCs creates "an elevation in civility of police and community interactions."

Subject matter experts agree that implementing an effective BWC program requires a comprehensive understanding and exploration of key policy, technology, privacy, funding, training, and outreach considerations with direct input from all affected stakeholders, including law enforcement, prosecution, information technology, labor organizations, civic leaders, and community members.

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Research update: National Body-Worn Camera Toolkit by Michael D. White Professor, School of Criminology and Criminal Justice, Arizona State University

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Research FAQs

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Body-worn cameras (BWC) are only one of the tools available to law enforcement for improving community trust, transparency, and accountability. There are several benefits for law enforcement officers who wear BWCs. BWCs provide an additional layer of safety for the officer. Adoption of a BWC program can represent a law enforcement department's effort to demonstrate transparency and accountability. In several studies, community member complaints against officers decreased following adoption of BWCs (Katz et al., 2015; Ariel, Farrar, & Sutherland, 2014; Mesa Police Department, 2013). The results from these studies are supported by in-person interviews with 40 law enforcement executives conducted by the Police Executive Research Forum (PERF). In one study, use-of-force by law enforcement officers decreased following adoption of BWCs (Ariel, Farrar, & Sutherland, 2014). Continuing research seeks to identify the underlying cause of the benefits. Additionally, video from BWCs may assist with prosecution of criminal cases or assist in the review of community members' complaints against officers. While research in Great Britain supports this potential evidentiary benefit, research in the United States has not sufficiently investigated the evidentiary value of BWCs (Goodall, 2007).

During the February 26-27, 2015 Bureau of Justice Assistance BWC Expert Panel, Inspector Steve Goodier of the Hampshire Constabulary in the United Kingdom shared highlights from their yearlong study of 180 body-worn videos. He cited reductions in crime, police-generated incidents, and assaults against police officers. The Inspector further explained "a large-scale public opinion survey was done before and after program implementation that concluded 85% of the public support for BWC technology. This survey was complemented by an officer survey–an overwhelming positive for support for BWCs."

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Available research consistently shows that officer body-worn cameras (BWC) contribute to a substantial and significant reduction in complaints against law enforcement officers. For example, in Rialto, CA, community member complaints against officers dropped by 88% after BWCs were deployed in the field (Ariel et al., 2014). In Mesa, AZ, BWCs were associated with a 60% decrease in complaints against law enforcement (Mesa Police Department, 2013). In Phoenix, AZ, complaints against officers who wore the cameras declined by 23%, compared to a 10.6% increase among comparison officers and 45.1% increase among patrol officers in other precincts (Katz et al., 2015).

Law enforcement executives agree that BWCs reduce complaints. Former Police Chief Ron Miller of Topeka, KS, stated, "There's absolutely no doubt that having BWCs reduces the number of complaints against officers." (PERF, 2014: 6) The reasons BWCs may cause reductions in community member complaints are not known. During the February 26-27, 2015 Bureau of Justice Assistance (BJA) BWC Expert Panel, Dr. Michael D. White of Arizona State University highlighted the importance of these findings and noted that the cameras may cause improved behavior ("civilizing effect"), may influence community member reporting rates (less likely to file complaints, especially frivolous complaints), or both. A number of law enforcement executives indicated that their officers have observed that BWCs discourage members of the public from filing unfounded complaints. More research is needed (especially in identifying the underlying cause of the benefit), but the consistency of the complaint reduction findings is notable.

BWCs can improve relationships between law enforcement and communities but are not a panacea, and community engagement should occur before or simultaneous to implementation. Joe Perez, President of the Hispanic American Police Command Officers Association - National Capitol Region, stated during the BJA BWC Expert Panel, "in regards to building trust with communities, having a BWC isn't going to build a better relationship with the community. Relationships need to be built before putting on the camera. Just because I put on a camera doesn't mean that it's building a relationship or more trust." Kay Chopard Cohen, Executive Director of the National District Attorneys Association, stated, "If a chief is worried about community relationships, then the chief has to do more than just give an officer a camera. He or she needs to go out and engage the community." Michael Kurtenbach of the Phoenix (AZ) Police Department added, "Develop relationships with the community on the front-end because it's too late to try to make those connections after an incident."

Also during the BWC Expert Panel, Inspector Steve Goodier of the Hampshire Constabulary in the United Kingdom shared highlights from their yearlong study of 180 body-worn videos citing reductions in crime, police-generated incidents, and assaults against police officers. Inspector Goodier further explained that "a large-scale public opinion survey was done before and after program implementation that concluded 85% of the public support for BWC technology. This survey was complemented by an officer survey–an overwhelming positive for support for BWCs.""

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In Rialto, CA, there were 61 use-of-force incidents before deployment of body-worn cameras (BWC) and just 25 incidents after deployment (a 60% drop). Additionally, "control" work shifts (officers who were not wearing cameras) produced double the number of use-of-force incidents compared to "treatment" shifts (camera-wearing officers) during the same period. The study in Mesa, AZ, also found significant reductions in use-of-force among officers wearing cameras, but in Phoenix, AZ, there was no significant difference in use-of-force incidents among camera-wearing and non-camera-wearing officers. Much more research needs to be conducted to determine whether BWCs reduce use-of-force by law enforcement. In addition, the Office of Community Oriented Policing Services Implementation Guide emphasizes that BWCs produce benefits in terms of change in behavior (civilizing effect), but those benefits can only be realized if the community member is aware of the recording.

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There are a number of ongoing studies, many of which are using randomized controlled trial designs. The National Institute of Justice is currently funding studies in Las Vegas (NV) and Los Angeles (CA). The Laura and John Arnold Foundation is funding studies in Spokane (WA), Tempe (AZ), Anaheim (CA), Pittsburgh (PA), and Arlington (TX), as well as a national cost-effectiveness study. A number of other research studies are underway or in the planning stages in the United States and United Kingdom, including Pensacola and West Palm Beach (FL), Orlando (FL), Greenwood (IN), Miami Beach (FL), Oakland (CA), and the Isle of Wight and Essex (United Kingdom).

Currently, we do not have an accurate estimate of the number of law enforcement agencies that have initiated body-worn camera (BWC) programs. Several law enforcement agencies in the United Kingdom were experimenting with BWCs as far back as 2005. In August 2013, the Police Executive Research Forum (PERF) surveyed 500 law enforcement agencies regarding their use of BWCs. Of the 254 agencies that responded, just 25% (n=63) indicated that they deployed BWCs. Interest in the technology has grown tremendously since then. One BWC vendor advertised in February 2015 that its product has been purchased by 4,000 law enforcement agencies worldwide, but this figure has not been verified. One expert has estimated that between 4,000 and 6,000 law enforcement agencies are planning to adopt or have already adopted BWCs. The Bureau of Justice Statistics (BJS) is performing a survey to better understand the number of law enforcement agencies that have implemented a BWC program.

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Yes, there is some evidence that suggests that body-worn cameras (BWC) improve the likelihood of successful prosecutions. In Phoenix, AZ, a Bureau of Justice Assistance-sponsored project examined the impact of BWCs on domestic violence case processing, concluding the following: "Analysis of the data indicated that following the implementation of body-worn cameras, cases were significantly more likely to be initiated, result in charges filed, and result in a guilty plea or guilty verdict. The analysis also determined that cases were completed faster following the implementation of body-worn cameras, (in part because of the) addition of a court liaison officer who facilitated case processing between the Phoenix (AZ) Police Department and city prosecutor's office." (Katz et al., 2015)

Agencies have varied considerably in the content and structure of their department policies. Many agencies have made their policies publicly available, or they will furnish their policy upon request. A number of policies have been collected by the Bureau of Justice Assistance and are available in this toolkit. In addition, there are currently several model policies available for review. The International Association of Chiefs of Police has devised a model policy. The Police Executive Research Forum (PERF) report (PERF, 2014) also includes a number of policy recommendations. In the United Kingdom, policy resources are available through a United Kingdom Home Office report (Goodall, 2007).

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There has been little research conducted on the effect of body-worn cameras (BWC) on criminal prosecutions. In Phoenix, AZ, researchers found that domestic violence cases involving a camera-wearing officer were more likely to be initiated by the prosecutor’s office (40.9% vs. 34.3%), have charges filed (37.7% vs. 26%), have cases furthered (12.7% vs. 6.2%), result in a guilty plea (4.4% vs. 1.2%), and result in a guilty verdict at trial (4.4% vs. 0.9%) (Katz et al., 2015).

The Plymouth (England) Head Camera Project reported that the technology increased officers’ ability to document that a violent crime had occurred, and the incidents recorded by BWCs were more likely to be resolved through guilty pleas rather than criminal trials (Goodall, 2007). In Renfrewshire, Scotland, BWC cases were 70-80% more likely to result in a guilty plea, compared to other court cases. A more recent report from Essex, Scotland, that focused specifically on domestic abuse calls also found that criminal charges were more likely to be filed in cases where an officer was wearing a BWC (Owens et al., 2014).

Anecdotal evidence from the Police Executive Research Forum (PERF) interviews of law enforcement executives (PERF, 2014) also suggests that BWCs may affect prosecution of cases through improved evidence collection. Chief Parker of the Dalton (GA) Police Department reported that BWCs have enhanced evidence collection at accident scenes, as officers work to secure a scene, interview witnesses and victims, and provide emergency medical care as needed. Several chiefs also indicated that BWCs are useful in domestic violence cases when it is difficult for a victim to participate. In these cases, BWC policies regarding victims, to include children and other vulnerable persons, must be carefully crafted.

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There are a handful of useful resources on body-worn cameras (BWC). The Police Executive Research Forum (PERF) and the Office of Community Oriented Policing Services (COPS) Office published a report in 2014 that examines key issues and offers policy recommendations. The report is based on survey responses from 254 agencies, interviews with 40 law enforcement executives who have implemented BWCs, and outcomes from a one-day conference held on September 11, 2013, that included more than 200 law enforcement executives, scholars, and experts. In April 2014, the Office of Justice Programs Diagnostic Center published a report that describes the core issues surrounding the technology and examines the state of research on those issues (White, 2014). In March 2014, the National Institute of Justice (NIJ) published a market survey that compared BWC vendors across a range of categories. There is also a growing number of published evaluations that examine the implementation, impact, and consequences of body-worn cameras. This web site and toolkit is intended to be a clearinghouse of the latest available research, reports, and knowledge on the technology.

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For additional evaluations from around the United States, United Kingdom, and Canada, see: Or view BWC Toolkit Research Resources with the category of Implementation Experiences

There is little empirical evidence on the impact of body-worn cameras (BWC) on community member complaint investigations. In Phoenix, AZ, researchers reported that camera-wearing officers who received a complaint were significantly less likely to have the complaint sustained, compared to non-camera-wearing officers and other patrol officers (Katz et al., 2015). Evidence from the United Kingdom also suggests that BWCs may result in quicker investigation of community member complaints against law enforcement (Goodall, 2007). The video evidence may also be used to provide members of the public with additional information that helps them understand the law enforcement officer’s behavior during a particular encounter (e.g., educational value). Legal scholar David Harris stated, "If citizens can see that they were, perhaps, mistaken, or that they did not understand the situation from the officer’s point of view, or that they did not have all the facts, they may come away with a better grasp of the situation, and feeling that they need not continue with the complaint process." (Harris, 2010: 7)

There is also some evidence to suggest that BWCs can assist with the investigation of critical incidents, including officer-involved shootings. Former Chief of Police Miller of the Topeka (KS) Police Department stated that a local district attorney cleared one of his officers of any wrongdoing during a critical incident after reviewing the BWC footage of the deadly shooting (PERF, 2014).

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The decision by a law enforcement agency to implement a body-worn camera (BWC) program represents an enormous investment of time and resources. The following are some of the concerns related to BWC programs:

  • Buying the hardware and managing the data: In January 2015, the acting Chief of the Phoenix (AZ) Police Department announced that it would cost the department $3.5 million to outfit its 3,000 officers with body-worn cameras and manage the BWC program. Overall, the costs vary depending on the type of camera, type of storage, IT support, and use of video. Agencies have been able to save money by joining with other agencies to purchase cameras and storage.
  • Privacy considerations: Privacy rights of the public are a primary concern. BWCs have the potential to impinge on community members' expectation of privacy. The technology may also present concerns for vulnerable populations such as children and victims of crime. Law enforcement agencies should fully investigate state privacy laws and engage relevant stakeholder groups (e.g., victim advocacy groups) before adopting BWCs. Officer privacy should also be addressed. Some law enforcement unions have opposed BWCs, arguing that adoption of the technology must be negotiated as part of the collective bargaining agreement. Also, at the February 26-27, 2015 Bureau of Justice Assistance BWC Expert Panel, some of the audience expressed concerns about BWCs because the technology gives supervisors the opportunity to go on "fishing expeditions" against officers in their command. Discussions among law enforcement executives and line officers are an important aspect of the policy development for implementing a BWC program.
  • Prosecution: Prosecutors and defense attorneys will want to review BWC video related to their cases, but they too have an obligation to protect the privacy of community members captured in the video. Therefore, it is important that the impact on prosecutorial and defense bar resources is taken into account when implementing a BWC program.
  • Policy development: During the BWC Expert Panel, participants shared very specific concerns and examples about BWC policy. For instance, Maggie Goodrich of the Los Angeles Police Department discussed her agency's concerns about ensuring officers always consider safety first and not put themselves in danger because of any additional distraction caused by the cameras. Assistant Chief Michael Kurtenbach of the Phoenix (AZ) Police Department walked through an example of a video used in a prosecution that resulted in an assault conviction of the officer. Triggered by the egregious behavior in the video, the agency reviewed three months of prior video to discover a pattern of inappropriate behavior. Upon the officer’s termination, the police union expressed concerns about evaluation of prior video, because the department had said it would not use video for administrative purposes. Kurtenbach suggested this illustrates the need for thoughtful consideration of policies even though, in this example, "once the videos were seen everyone agreed the officer should be fired."
  • Training considerations: Law enforcement agencies should plan for additional training on camera use, video review, and video expungement and redaction.
  • Advocacy considerations: Cynthia Pappas from the Office of Juvenile Justice and Delinquency Prevention reminded BWC Expert Panel participants that "95% of youth and juveniles commit non-violent offenses so there should be great precautions made to protect them, including protections from public screening" of the video. Krista Blakeney-Mitchell from the Office on Violence Against Women went on to describe how victim confidentiality should be addressed during a call for assistance for domestic violence. If an officer is entering the home of a domestic violence victim, the victim is exposed. "We need to consider how that plays out later in recordings. Will the video be used against the victim based on her demeanor near the time of the incident? Will she be re-victimized?" Another concern is the use of BWCs when dealing with sexual assault victims and the need to decide how video will be used in these situations. Lastly, Blakeney-Mitchell explained that it is "hard for victims to come forward when everyone will know their story based on video footage…there is a concern that victim reporting will go down."
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Departments vary in how they have implemented body-worn camera (BWC) programs. However, there are two common themes.

First, the vast majority of departments have implemented their BWC programs with officers assigned to patrol. The rationale for deploying the technology with front-line patrol officers is that officers on patrol have the most contact with the public. Some departments have also expanded their use of BWCs beyond patrol into specialized units such as K-9, SWAT, specialized driving under the influence teams, and investigations.

Second, many departments have adopted an incremental approach to deployment by restricting use to a small number of officers for an initial pilot period. Departments have found that this type of approach helps to overcome potential officer anxiety and resistance and enables a department to make mid-term revisions as it learns how this technology affects the community as a whole. Such a strategy also allows other units in the department the time to adapt to the new technology. In many cases, the initial group of officers assigned to wear cameras are volunteers who often become "internal champions" for the technology.

Lindsay Miller from the Police Executive Research Forum stated, "The decision to implement a BWC program should not be entered lightly–once implemented it is hard to scale back from that course. Agencies need to thoughtfully examine the idea of a BWC program and have written policies in place (something not all agencies do)."

This toolkit is community-sourced. That is, most of the material in this clearinghouse was contributed by your colleagues representing various disciplines from across the country and the world, and it is available for your use, education, and consideration. If you use content from the toolkit, we only ask that you attribute the material to the web site or the original author of the material. This toolkit does not endorse any one resource but asks you to evaluate the appropriate resources for your communities’ needs as you work your way through the National Body-Worn Camera Toolkit Law Enforcement Implementation Checklist. And, if you have something to contribute, just e-mail us at askbwc@usdoj.gov.

The answer to this question depends on how you measure officer daily practices.

With regard to paperwork, the research is mixed. In Plymouth, England, body-worn cameras (BWC) led to quicker resolution of cases, which produced a 22.4% reduction in officer time devoted to paperwork and file preparation; and to a 9.2% increase in officer time spent on patrol (an extra 50 minutes per nine-hour shift) (Goodall, 2007). But in Victoria, Canada, and in Phoenix, AZ, officers spent significantly more time on paperwork following the deployment of BWCs (Laur et al., 2010; Katz et al., 2015).

With respect to evidentiary quality, research conducted in Plymouth and Essex, United Kingdom; Victoria, Canada; and Phoenix, AZ, suggests that the use of BWCs increases the quality of evidence (Goodall, 2007; Laur et al., 2010; Owens et al., 2014; Katz et al., 2015). Related to these results, in Phoenix researchers reported that domestic violence incidents where an officer was wearing a BWC were more likely to result in charging and conviction. Specifically, they found that when compared to non-camera cases, camera cases were more likely to be initiated by the prosecutor’s office (40.9% vs. 34.3%), have charges filed (37.7% vs. 26%), have cases furthered (12.7% vs. 6.2%), result in a guilty plea (4.4% vs. 1.2%), and result in a guilty verdict at trial (4.4% vs. 0.9%) (Katz et al., 2015).

If officer performance is measured by the number of contacts with members of the public, the evidence is limited. In Rialto, CA, there was an increase in the number of contacts between law enforcement and the public after BWCs were deployed in the field (3,178 more contacts after BWC deployments, compared to the prior year) (Ariel, et al. 2014). We do not know why there was this increase but intend to do further research to find out if an increase is consistent with what is happening with other departments and why.

More generally, a number of law enforcement executives interviewed indicated that they had used BWCs to identify and address larger structural issues in their department and to develop solutions to those problems. This includes weaknesses in training, policy, and law enforcement officer field behavior (e.g., using video footage to investigate racial profiling) (PERF, 2014).

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There is currently no evidence from the United States documenting any sort of health and safety risks associated with body-worn cameras. The United Kingdom Home Office guide provides a comprehensive list of potential hazards to officers who wear head-mounted cameras, rates the risk level for each hazard, and discusses strategies to mitigate risk. Many of the hazards are deemed to be low-risk, such as being targeted for assault because of the camera, neck injury from the weight of the camera, and electrical shock. However, several hazards are rated as medium-risk, such as strangulation with the lead (or wire) by an offender; head injury through impact of the camera by an assailant; and soreness, discomfort, and headache from the headband. Most of the cited health concerns are mitigated by wearing the camera on other parts of the uniform (e.g., the torso, not the head). The lack of evidence regarding the health and safety concerns does not mean there are no risks. Departments should explore potential risks as they adopt the technology.

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There is potential to integrate body-worn cameras (BWC) with facial recognition systems. The use of facial recognition and BWCs may pose serious risks to public privacy. Agencies that explore this integration should proceed very cautiously and should consult with legal counsel and other relevant stakeholders.

The acquisition, implementation, and use of body-worn camera (BWC) video in state, local, and tribal law enforcement agencies can be a costly and complex process. This toolkit was developed by the Bureau of Justice Assistance in partnership with an expert panel of criminal justice practitioners with BWC experience to provide law enforcement agencies with the resources necessary to implement officer BWCs in an efficient, equitable, and effective way. This toolkit seeks to help you become familiar with a broad array of considerations to include:

  • Defining concrete steps to follow for successful planning and implementation of a BWC program.
  • Identifying personnel and internal organizational challenges to an agency when implementing a BWC initiative, to include training and labor management considerations.
  • Discussing technical issues associated with the implementation of BWCs.
  • Assessing the impact of BWCs and the evidence they collect on a law enforcement agency and the entire criminal justice system, including courts, prosecutors, defense attorneys, and victims.
  • Recognizing privacy and legal issues as they relate to members of the public, a law enforcement agency, and the accused.

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