Overview of Body-Worn Camera Use by Law Enforcement
Body-worn cameras are widely used by state and local law enforcement agencies in the United States. They are worn principally by officers in the performance of duties that require open and direct contact with the public. Despite their widespread and growing adoption, the current evidence regarding the effectiveness of body-worn cameras is mixed. Some studies suggest that body-worn cameras may offer benefits while others show either no impact or possible negative effects. The mixed results of these studies strongly imply that additional research is needed. In particular, more studies employing randomized control trials  are needed.
Use of Body-Worn Cameras
In November 2018, the Bureau of Justice Statistics (BJS) published a report on the use of body-worn cameras by law enforcement agencies in the United States in 2016. This report showed that:
- 47% of general-purpose law enforcement agencies had acquired body-worn cameras; for large police departments, that number is 80%.
- Among agencies that had acquired body-worn cameras, 60% of local police departments and 49% of sheriffs' offices had fully deployed their body-worn cameras.
- Overall, in agencies that had acquired body-worn cameras there were 29 body-worn cameras in service per 100 full time officers (expected to increase to 50/100 by late 2017).
- About 86% of general-purpose law enforcement agencies that had acquired body-worn cameras had a formal body-worn camera policy.
- Agencies not using body-worn cameras stated cost (hardware acquisition, video storage, system maintenance) to be the primary disincentive.
Are Body-Worn Cameras Effective?
According to the BJS report, the main reasons (about 80% each) that local police and sheriffs’ offices had acquired body-worn cameras were to improve officer safety, increase evidence quality, reduce civilian complaints, and reduce agency liability.
Research does not necessarily support the effectiveness of body-worn cameras in achieving those desired outcomes. A comprehensive review of 70 studies of body-worn cameras use found that the larger body of research on body-worn cameras showed no consistent or no statistically significant effects.
These mixed findings are further reflected in findings from evaluations of five body-worn camera programs that have met the stringent criteria for inclusion in NIJ’s CrimeSolution.gov. Across these evaluations, researchers looked at a range of outcomes, including use of force, citizen complaints, arrests, and assaults on officers.
Three of the body-worn cameras programs were rated Promising —
- In Birmingham, UK, evaluators found that deploying body-worn cameras resulted in a statistically significant reduction in citizen injury, but no statistically significant reduction in officer use of force or injury. Read the program profile Police Body-Worn Cameras (Birmingham South, UK).
- In Rialto, CA, evaluators found a statistically significant reduction in police use-of-force but no significant difference in citizen complaints. Read the program profile Police Body-Worn Cameras (Rialto, Calif.).
- In Las Vegas, Nevada, and evaluation of the Metropolitan Police Department’s use of body-worn cameras revealed that the use of body-worn cameras resulted in a statistically significant reduction in both complaints and use of force. Read the program profile Body-Worn Cameras (Las Vegas Metropolitan Police Department.
Two of the body-worn camera programs evaluated were found to have no effect or even negative effects —
- In Washington, DC, evaluators found no statistically significant differences in police use-of-force, nor the number of citizen complaints. Read the program profile Police Body-Worn Cameras (Washington, D.C.).
- A multi-site evaluation of eight departments in the US and the UK found, overall, found no statistically significant differences in police use of force, number of citizen complaints, or number of arrests for disorderly conduct for police officers who wore body-worn cameras, compared with officers who did not wear them. Read the program profile Police Body-Worn Cameras in Eight Police Departments in the United Kingdom and United States.
Based on these reviews and the existing research on the impact of body-worn cameras use, it is clear that further research is essential to determine the value of body-worn cameras use and potentially the more effective ways body-worn cameras could be deployed. Given the growing use of body-worn cameras, it would be best to build in rigorous evaluations as law enforcement agencies expand their use of this technology.
Primer on Body-Worn Cameras for Law Enforcement
Developed by the NIJ-funded NLECTC Sensor, Surveillance and Biometric Technologies Center of Excellence, A Primer on Body-Worn Cameras for Law Enforcement provides an introduction to body-worn camera systems. The report discusses the functions and features of body-worn camera systems and highlights issues and factors that law enforcement organizations should consider before and during implementation.
Technical Guidance on Body-Worn Camera Technologies
Agencies should consider how body worn cameras will meet their mission needs and requirements prior to procurement and use of the technology. To provide general guidance to law enforcement practitioners, NIJ, NIST and the FBI developed a table listing operating characteristics and associated functionality descriptions based on existing technical resources about criminal justice use of video., The operating characteristics and associated functionality descriptions in the table can help agencies determine what they need as they consider the commercial products available.
Market Survey of Body-Worn Cameras for Criminal Justice
The NIJ-funded NLECTC Sensor, Surveillance and Biometric Technologies Center of Excellence conducted a market survey on body-worn cameras for criminal justice. The survey, updated in 2016, aggregates and summarizes information on a number of makes and models of body-worn cameras available today, including the approximate costs of each unit.
[note 1] RCTs provide the highest degree of confidence that observed effects are the result of the program and not of other factors.
[note 2] Hyland, S., Body-Worn Cameras in Law Enforcement Agencies, 2016, Bureau of Justice Statistics, November 2018. Note that this survey excluded federal agencies, sheriffs’ offices with only jail or court duties, and special-purpose agencies such as transit police and campus police.
 Lum, C., et al, Research on body-worn cameras: What we know, what we need to know, Criminology & Public Policy, pp. 93 – 118, March 24, 2019
[note 4] CrimeSolutions.gov is the NIJ-funded federal clearinghouse of evaluation research, showing what works, what does not work, and what is promising across broad expanses of criminal and juvenile justice programs and practice. Learn more about CrimeSolutions.gov.
[note 5] Home Office Centre for Applied Science and Technology, Body-Worn Video Technical Guidance (pdf, 10 pages), May 2014
[note 6] Scientific Working Group on Imaging Technology, Recommendations and Guidelines for Using Closed-Circuit Television Security Systems in Commercial Institutions, Version 3.0 (pdf, 28 pages), June 8, 2012.