A recent spate of violence between police officers and citizens in the United States has raised many questions about what happens when an organization meant to protect its populace harms it instead. As with so many quandaries these days, technology is often at the center of the debate – namely, regarding the use of body-mounted cameras and the public release of the footage they capture. While body cams can often prove police misconduct, they can also exonerate officers who act appropriately given difficult situations. The simple tech can also, apparently, reduce complaints against cops, as shown in a recent University of Cambridge study.

The research project, which Cambridge calls one of the largest randomized-controlled experiments in the history of criminal justice research, found that when police officers wore body cameras, complaints against them went down by an astounding 93 percent. The study, called "Contagious Responsibility" has been published in the journal Criminal Justice and Behavior.

The study followed officers in five police stations across the UK (Northern Ireland, the West Midlands, West Yorkshire and Cambridgeshire), and two in the US (Rialto and Ventura, California). That encompassed 1,429,868 officer hours across 4,264 shifts covering a total population of about 2,000,000 citizens. The results showed a drop in complaints from 1,539 in the year preceding the trial – an average of 1.2 complaints per officer – to 113 complaints during the study, which averages out at .08 complaints per officer.

The research project followed on from a study done in 2012 that focused on the Rialto precinct, which showed that use-of-force by officers with body cams fell by 59 percent and complaints dipped by 87 percent versus the prior year.

"We have footage by mobile phone, or partial cameras of people walking by, and they only capture the story from when they turned on the cameras," said Barak Ariel from Cambridge's Institute of Criminology in a video released by the university (see below). "People don't walk around with their cameras on. But the body-worn video introduces a way to show the evidence not just from the officer's perspective, but from the very beginning of the story."

Interestingly, two other studies earlier this year (1, 2) showed that when police officers were in control of switching on and off the cameras themselves, their use-of-force actually climbed, so having continuously running video might be key to the success of the technology.

Doing so comes with its own challenge, however.

"It's very important to distinguish between two elements," said Ariel. "One is the capacity to record, and the other is the capacity to store. It's critically important to distinguish between the two, because that has implications on human rights. In many ways, you can and should record everything. But what you save, what you keep as evidence, is a distinctly different question."

While the investigators stress that more research is needed to tease out the complicated subject of body cameras, the police force in West Yorkshire – which Ariel says is the largest site to experiment with the technology – has seen a clear benefit.

"Anecdotally, in terms of bringing offenders to justice, our Crown Prosecution Service have said to us on numerous occasions, that the video footage has tipped the balance in favor of prosecution, whereas without it, they may not have been able to prosecute," said Jayne Sykes, the West Yorkshire Police Department's head of performance review. "And also, again anecdotally, we're getting more early guilty pleas from suspects which saves the victim the trauma of having to go to court and give evidence."

Another benefit of wearing the cameras is cost, according to Ariel, who says that the initial Rialto study showed that for every dollar spent, you save about US$4 on complaint litigation. As the cost of cameras continues to fall, the cost-to-value ratio should improve even more from there he adds.

The Cambridge University video below details the results of the study along with showing some pretty dramatic body-camera footage.

View gallery - 2 images