The recording of interactions with the public increases accountability on both sides, researchers say

This article is more than 3 years old

This article is more than 3 years old

Police equipped with body-worn cameras receive 93% fewer complaints from the public, according to a new study that suggests the technology helps to cool down potentially volatile encounters.

Academics at Cambridge University, whose research looked at nearly 1.5m beat hours across more than 4,000 shifts by officers in the UK and California, claim their findings suggest the cameras herald a “profound sea change in modern policing”.

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Lead author Dr Barak Ariel, from Cambridge’s Institute of Criminology, said: “The cameras create an equilibrium between the account of the officer and the account of the suspect about the same event – increasing accountability on both sides.”

Body-worn cameras have been increasingly used in both Britain and the US in recent years in response to a perceived crisis in police legitimacy and disproportionate targeting of ethnic minorities.

A report last year called for London’s Metropolitan police to use cameras during all stop and searches, amid persistent complaints that the force disproportionately targets young black men. In the US, the epidemic of police shootings of black people has raised similar concerns.

The Cambridge study, conducted during 2014-15 across seven trial sites that covered a population of more than 2 million people, set out to investigate the difference made by the cameras, which are usually attached to the top half of police uniforms.

Throughout the year-long experiment, researchers were said to have randomly assigned about half of the officers starting their shifts with cameras. All officers in the forces taking part worked with cameras at some point, the researchers said.

During the 12 months before the study, a total of 1,539 complaints were lodged against police in the areas examined, amounting to 1.2 complaints per officer. By the end, the number of complaints had fallen to 133 for the year across all sites – 0.08 per officer.

The researchers were surprised to find that there was no statistically significant difference between the number of complaints received by officers wearing cameras and those without, a result they said may be a result of “contagious accountability”.

Co-author Dr Alex Sutherland, of Rand Europe, said: “It may be that, by repeated exposure to the surveillance of the cameras, officers changed their reactive behaviour on the streets – changes that proved more effective and so stuck.

“With a complaints reduction of nearly 100% across the board, we find it difficult to consider alternatives, to be honest.”

The findings come with an important caveat, which is that the behaviour changes appeared to rely on cameras recording throughout encounters with the public, and officers explicitly warning that they were on, the researchers said.

Early findings from the study, published earlier this year, suggested that violence actually increased if a camera was switched on in the middle of an interaction, a move that could be interpreted by both sides as an escalation.

Ariel said that verbal reminders that encounters were being filmed encouraged participants “to think about their actions more consciously. This might mean that officers begin encounters with more awareness of rules of conduct, and members of the public are less inclined to respond aggressively.”

The study’s findings are published in the journal Criminal Justice and Behaviour.