Let's make the coppers wear cameras! That'll make the ba... Oh. No sodding difference

Large-scale randomised US trial: 'Recalibrate’ expectations

Police forces have been told to temper their expectations of body-worn cameras, as a randomised study involving almost 2,500 US cops throws up little evidence of purported benefits.

The work, carried out by an applied research team at the mayor’s office in Washington DC, claims to be one of the largest randomised control trials of the technology.

It aimed to assess widespread assertions that BWCs will make both police and citizens behave differently.

Such beliefs have encouraged governments across the world to invest heavily in the tech - a survey of the UK’s police forces indicated they have spent upwards of £22m on BWCs, while councils have forked out almost £1.8m on body worn video technology.

However, there is mixed evidence as to whether this is the case, and a number of trials have failed to find consistent effects on behaviour.

The latest study (PDF), from Lab @ DC, involved 2,224 of the 3,800 members of the Metropolitan Police Department in Washington, DC, and - unlike some other trials - randomised the officers, not the shift, meaning officers were not in both the treatment and control group.

The team then looked at data in four categories: the self-reported use of force by officers, civilian complaints, police activities like traffic tickets or warnings issued, and judicial outcomes.

It found that, for each of these categories, the average treatment effect was “very small” with no estimate reaching statistical significance.

“As such, our experiment suggests that we should recalibrate our expectations of BWCs,” the authors wrote in the paper.

Law enforcement agencies considering buying BWCs “should not expect dramatic reductions in use of force or complaints, or other large-scale shifts in police behaviour, solely from the deployment of this technology”, the authors said.

They add that forces should “temper expectations” about the value of evidence from BWCs, noting that - although the court data the study used had some limitations - “preliminary analyses do not uncover any clear benefits”.

The team said that this could be because the devices simply don’t change behaviour - possibly because the officer and citizen aren’t aware of the cam, or because other factors override any deterrent effect the BWC might have.

There is also the possibility that knowing one cop on the team has a cam might change the actions of those without them, or that those with BWCs are more likely to self-report use of force, as they know it has been taped.

Finally, the researchers acknowledged that Washington could be a distinct example, given its officers receive training to handle high-profile, large-scale events. They also note that the team has undertaken several reforms to reduce police misconduct.

Nonetheless, the authors concluded that - based on these results - although BWCs “may have great utility in specific policing scenarios”, forces should not expect department-wide improvements in outcomes.

Renate Samson, chief exec of civil liberties group Big Brother Watch, which has regularly lobbied against the use of BWCs by UK police, urged forces police to heed this advice.

“There are still so many unanswered questions on it, and yet forces are spending millions on the technology,” she said.

“If you can’t show that spending is value for money, you need to question whether it’s the right tech to be using.” ®

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