Updates to what the evidence tells us about body-worn cameras
NIJ has continued to review the available evidence on the effectiveness of body worn cameras, including rating programs and practices on CrimeSolutions. See Research on Body-Worn Cameras and Law Enforcement.
In 1829, Sir Robert Peel — regarded by many as the father of modern policing — developed what came to be known as the Nine Principles of Law Enforcement, which were given to British law enforcement officers as general instructions. Peel’s second principle stated, “The ability of the police to perform their duties is dependent upon public approval of police existence, actions, behavior and the ability of the police to secure and maintain public respect.”[1]
Nearly 200 years later, Peel’s principle still holds true: The ability of law enforcement to fight crime effectively continues to depend on the public’s perception of the legitimacy of the actions of officers. A number of recent civil disturbances across the United States subsequent to instances of lethal use of force by officers highlight the ongoing challenges in maintaining the public’s perceptions of law enforcement legitimacy, particularly as it concerns the use of force.
Body-worn cameras have been viewed as one way to address these challenges and improve law enforcement practice more generally. The technology, which can be mounted on an officer’s eyeglasses or chest area, offers real-time information when used by officers on patrol or other assignments that bring them into contact with members of the community. Another benefit of body-worn cameras is their ability to provide law enforcement with a surveillance tool to promote officer safety and efficiency and prevent crime.
This technology has diffused rapidly across the United States. In 2013, approximately one-third of U.S. municipal police departments had implemented the use of body-worn cameras.[2] Members of the general public also continue to embrace the technology. But what does the research tell us? Current studies suggest that body-worn cameras may offer benefits for law enforcement, but additional research is needed to more fully understand the value of the technology for the field.
Potential Benefits
Proponents of body-worn cameras point to several potential benefits.
Better transparency. First, body-worn cameras may result in better transparency and accountability and thus may improve law enforcement legitimacy. In many communities, there is a lack of trust and confidence in law enforcement. This lack of confidence is exacerbated by questions about encounters between officers and community members that often involve the use of deadly or less-lethal force. Video footage captured during these officer-community interactions might provide better documentation to help confirm the nature of events and support accounts articulated by officers and community residents.[3]
Increased civility. Body-worn cameras may also result in higher rates of citizen compliance to officer commands during encounters and fewer complaints lodged against law enforcement. Citizens often change their behavior toward officers when they are informed that the encounter is being recorded. This “civilizing effect” may prevent certain situations from escalating to levels requiring the use of force and also improve interactions between officers and citizens.[4]
Quicker resolution. Body-worn cameras may lead to a faster resolution of citizen complaints and lawsuits that allege excessive use of force and other forms of officer misconduct. Investigations of cases that involve inconsistent accounts of the encounter from officers and citizens are often found to be “not sustained” and are subsequently closed when there is no video footage nor independent or corroborating witnesses. This, in turn, can decrease the public’s trust and confidence in law enforcement and increase perceptions that claims of abuse brought against officers will not be properly addressed. Video captured by body-worn cameras may help corroborate the facts of the encounter and result in a quicker resolution.
Corroborating evidence. Footage captured may also be used as evidence in arrests or prosecutions. Proponents have suggested that video captured by body-worn cameras may help document the occurrence and nature of various types of crime, reduce the overall amount of time required for officers to complete paperwork for case files, corroborate evidence presented by prosecutors, and lead to higher numbers of guilty pleas in court proceedings.
Training opportunities. The use of body-worn cameras also offers potential opportunities to advance policing through training. Law enforcement trainers and executives can assess officer activities and behavior captured by body-worn cameras — either through self-initiated investigations or those that result from calls for service — to advance professionalism among officers and new recruits. Finally, video footage can provide law enforcement executives with opportunities to implement new strategies and assess the extent to which officers carry out their duties in a manner that is consistent with the assigned initiatives.
Current Research Findings
The increasing use of body-worn cameras by law enforcement agencies has significantly outpaced the body of research examining the relationship between the technology and law enforcement outcomes. As detailed below, although early evaluations of this technology had limitations, some notable recent research has helped advance our knowledge of the impact of body-worn cameras.
In a 2014 study funded by the Office of Justice Programs Diagnostic Center, researcher Michael White noted that earlier evaluations of body-worn cameras found a number of beneficial outcomes for law enforcement agencies.[5] The earliest studies conducted in the United Kingdom indicated that body-worn cameras resulted in positive interactions between officers and citizens and made people feel safer. Reductions in citizen complaints were noted, as were similar reductions in crime. The studies found that the use of body-worn cameras led to increases in arrests, prosecutions, and guilty pleas.[6] From an efficiency standpoint, the use of the technology reportedly enabled officers to resolve criminal cases faster and spend less time preparing paperwork, and it resulted in fewer people choosing to go to trial.
Studies that followed in the United States also provided support for body-worn cameras; however, a number of them were plagued with dubious approaches that called the findings into question. According to White, the few studies that were conducted between 2007 and 2013 had methodological limitations or were conducted in a manner that raised concerns about research independence. For example, several studies included small sample sizes or lacked proper control groups to compare officers wearing body-worn cameras with officers not wearing them. Some studies were conducted by the participating law enforcement agency and lacked an independent evaluator. Finally, a number of the studies focused narrowly on officer or citizen perceptions of body-worn cameras instead of other critical outcomes, such as citizen compliance and officer or citizen behavior in instances involving use of force.
Over time, scientific rigor improved, and studies conducted in U.S. law enforcement agencies produced findings that indicated promising support for body-worn cameras. For example, in 2014, researchers at Arizona State University (funded through the Bureau of Justice Assistance’s Smart Policing Initiative) found that officers with body-worn cameras were more productive in terms of making arrests, had fewer complaints lodged against them relative to officers without body-worn cameras, and had higher numbers of citizen complaints resolved in their favor.[7] Another study conducted with the Rialto (California) Police Department noted similar decreases in citizen complaints lodged against officers wearing body-worn cameras as well as decreases in use-of-force incidents by the police.[8] In addition, Justin Ready and Jacob Young from Arizona State University found that officers with body-worn cameras were more cautious in their actions and sensitive to possible scrutiny of video footage by their superiors. Also, contrary to initial concerns, officers who wore cameras were found to have higher numbers of self-initiated contacts with community residents than officers who did not wear cameras.[9]
Recent randomized controlled trials, which are considered the scientific gold standard for evaluating programs, have also been conducted on body-worn cameras. Of the various scientific methods available, these trials have the greatest likelihood of producing sound evidence because random assignment is able to isolate a specific treatment of interest from all of the other factors that influence any given outcome. In a 2016 global, multisite randomized controlled trial, Barak Ariel and colleagues found that use-of-force incidents may be related to the discretion given to officers regarding when body-worn cameras are activated during officer-citizen encounters. The researchers found decreases in use-of-force incidents when officers activated their cameras upon arrival at the scene. Alternatively, use-of-force incidents by officers with body-worn cameras increased when the officers had the discretion to determine when to activate their cameras during citizen interactions.[10]
In 2017, with NIJ support, researchers from CNA conducted a randomized controlled trial on 400 police officers in the Las Vegas Metropolitan Police Department. The research team found that officers with body-worn cameras generated fewer use-of-force reports and complaints from citizens compared to officers without body-worn cameras. Additionally, officers with body-worn cameras issued higher numbers of arrests and citations compared to officers without body-worn cameras.[11]
More Research Is Needed
An increasing number of studies have emerged to help fill knowledge gaps in the current body of research on body-worn cameras. Researchers at George Mason University noted that 14 studies have been completed and at least 30 others are currently examining the impact of body-worn cameras on various outcomes.[12] The most common outcomes examined include the impact of body-worn cameras on the quality of officer-citizen interactions measured by the nature of the communication, displays of procedural justice and professionalism, and misconduct or corruption; use of force by officers; attitudes about body-worn cameras; citizen satisfaction with law enforcement encounters; perceptions of law enforcement and legitimacy; suspect compliance with officer commands; and criminal investigations and law enforcement-initiated activity.[13]
However, knowledge gaps still exist. The George Mason University researchers highlighted the need to examine organizational concerns regarding body-worn cameras. For example, little attention has been focused on improvements in training and organizational policies. Additional information is also needed on how body-worn cameras can help facilitate investigations of officer-involved shootings or other critical incidents, and on the value of video footage captured by body-worn cameras in court proceedings.
Current research varies by level of rigor and methods used, but the results continue to help law enforcement executives decide whether to adopt this technology in their agencies. Overall, the research on body-worn cameras suggests that the technology may offer potential benefits for law enforcement. However, the true extent of its value will depend on the continuation of research studies to keep pace with the growing adoption and implementation of body-worn cameras by law enforcement agencies in the United States.
For More Information
Read more about NIJ’s work in body-worn cameras.
Visit the Bureau of Justice Assistance’s Body-Worn Camera Toolkit.
About This Article
This article was published as part of NIJ Journal issue number 280, December 2018.
This article discusses the following grant “Research on the Impact of Technology on Policing Strategies,” grant number 2013-IJ-CX-0016