The study, conducted by UNLV's Center for Crime and Justice Policy and Virginia-based non-profit research organization CNA in coordination with the Las Vegas Metropolitan Police Department (LVMPD), also found that body-worn cameras can generate considerable cost savings for police by simplifying the complaint resolution process.

According to study authors, "these results are consistent with the perceived benefits of the body-worn camera technology and support the notion that body-worn cameras can help to improve relations between police and communities."

美国司法部的国家研究所e of Justice funded the study beginning in 2014 to determine the impact of the relatively recent technology on a variety of outcomes related to use of force, misconduct, and to detail the cost-benefit of the cameras. LVMPD was one of the first large police agencies in the U.S. to equip its officers with body-worn cameras.

"Body worn cameras demonstrate a police agency's commitment to transparency and accountability," said study co-author William Sousa, director of UNLV's Center for Crime and Justice Policy. "The results of this study suggest that the cameras also have benefits in terms of reductions in police use of force and complaints of officer misconduct."

Using a randomized controlled trial, approximately 400 LVMPD officers were assigned into one of two groups: a "treatment" group with body-worn cameras and a "control" group without. After one year in the trial, the number of officers with at least one complaint of misconduct had decreased 30 percent for officers with body-worn cameras, but had decreased only 5 percent for control officers. Similarly, the number of officers with at least one use of force incident had decreased 37 percent for officers with body-worn cameras, but incidents increased 4 percent for control officers. Body-worn cameras were also associated with more citations issued (an increase of 8 percent) and more arrests made (an increase of 6 percent).

The analysis also revealed a significant overall cost savings due to fewer complaints of misconduct and fewer resources spent on misconduct investigations. The study cited costs of body-worn cameras between $828 and $1,097 per user, per year. The cost savings from fewer misconduct complaints and investigations were estimated by authors to be more than $4,000 per user annually.

"This research, part of a growing body of rigorous research regarding body-worn cameras, provides valuable information to the increasing number of police agencies implementing body-worn cameras in the United States," said Chip Coldren, managing director of justice programs at CNA and one of the report's authors. "It provides compelling evidence cameras can generate savings by simplifying complaint resolution, which can add up to millions of dollars for a major city and lead to large reductions in the use of force by police."

The full report can be found here:https://www.cna.org/cna_files/pdf/IRM-2017-U-016112-Final.pdf