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30th December 2014

Police body cameras can prevent excessive force

The first full scientific study into police body cameras has shown the technology can substantially reduce both excessive use-of-force by officers and complaints against officers by the public.


police body camera
By Throwawaysixtynine (Own work) [CC BY 4.0], via Wikimedia Commons


The first full scientific study of an experiment with body-worn police cameras has been published by the Journal of Quantitative Criminology. The trial was conducted in Rialto, California, during a 12-month period and shows highly promising results. Officers wearing the camera devices witnessed a 59% drop in their use-of-force, while complaints against them fell by a massive 87% compared to the previous year's figures. Police shifts were randomly assigned as experimental (with camera) or control (without camera), totalling over 50,000 hours of police-public interactions.

According to the researchers, when people are being recorded, it generates a "self-awareness" for everyone involved. Knowing a third party could later observe their actions – potentially a legal court, or the public – will cause them to change their behaviour and become less confrontational. This makes body-worn video a "preventative treatment" that could diffuse or even completely stop volatile situations from escalating. It applies to both abusive behaviour towards police and unnecessary use-of-force by police.

Dr Barak Ariel, from the University of Cambridge's Institute of Criminology (IoC): "With institutionalised body-worn-camera use, an officer is obliged to issue a warning from the start that an encounter is being filmed, impacting the psyche of all involved by conveying a straightforward, pragmatic message: we are all being watched, videotaped and expected to follow the rules."

"Police subcultures of illegitimate force responses are likely to be affected by the cameras, because misconduct cannot go undetected – an external set of behavioural norms is being applied and enforced through the cameras. Police-public encounters become more transparent and the curtain of silence that protects misconduct can more easily be unveiled, which makes misconduct less likely."


police body camera video footage
Screen capture from a Rialto PD officer's body-worn-camera. Credit: Rialto PD


The trials are now being replicated by 30 forces worldwide – including the Metropolitan Police in London, forces in West Yorkshire, Northern Ireland, Uruguay and elsewhere in the United States. In the wake of several high-profile incidents, the White House earlier this month pledged $263 million in additional federal funding for police training and cameras, with $75 million allocated specifically for the purchase of 50,000 body cameras. New findings are due to be announced at the IoC's Conference for Evidence-Based Policing in July 2015. Early signs appear to match the Rialto success, showing that body-worn-video cameras have a major positive impact on interactions between officers and civilians.

However, the research team is keen to sound a note of caution. Just as with any revolutionary new technology, more needs to be known regarding the full effects and legal ramifications. Before departments are "steamrolled" into adopting them, vital questions need to be answered such as how these devices might influence prosecution outcomes.

"Historically, courtroom testimonies of response officers have carried tremendous weight," says Ariel. "But prevalence of video might lead to reluctance to prosecute when there is no evidence from body-worn-cameras to corroborate the testimony of an officer, or even a victim."

There are also the issues of storage, security, privacy and the vast amount of data captured. While the devices are highly cost-effective at present (analysis from Rialto showed every dollar spent on the technology saved about four dollars on complaint litigations), the sheer level of data storage has the potential to become crippling in the future.

"The velocity and volume of data accumulating in police departments – even if only a fraction of recorded events turn into 'downloadable' recordings for evidentiary purposes – will exponentially grow over time," says Ariel. "User licenses, storage space, 'security costs', maintenance and system upgrades can potentially translate into billions of dollars worldwide."

"Body-worn-video has the potential to improve police legitimacy and enhance democracy – not least by calming situations on the front line of policing to prevent the pain and damage caused by unnecessary escalations of volatile situations. But there are substantial effects of body-worn-video that can potentially offset the benefits which future research needs to explore."


police officers body cameras press conference
Police officers demonstrate body cameras at a recent press conference in Washington DC. Credit: Lateef Mangum/Washington DC Mayor's Office


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