Opening up the black box of body cameras

In November 2017, police-officers and academics from all over Europe got together to learn from each other. This edition of the annual CEPOL-conference was in Budapest and the theme was innovation. I presented a paper on body-cameras: “Opening up the black box: understanding the impact of body cameras on policing”.

Everybody happy?

In my presentation, I started with the simple but surprising observation that bodycams, also called Body-Worn Cameras (BWC) or Body Worn Video (BWV), seem to have only supporters. Politicians, police, press, privacy advocates and the public – almost everybody wants the police to use bodycams. I have been studying other types of surveillance for twenty years and never before have I seen this much support from such a wide range of people. Even civil rights activists who generally do not eagerly embrace new forms of surveillance, press the police to introduce body-cams because they believe they can be helpful when police officers are not doing their jobs properly. And they have a point: it’s not hard at all to find clips on-line that show police officers engaged in activities that couldn’t possibly make the police proud.

So, a logical question would be why most police forces themselves seem eager to work with bodycams too? I’ve discovered that this is because most police officers are not aware of what a bodycam actually is until after they have been implemented. This lack of knowledge creates a lot of room for advocates of the technology to focus on the benefits (that are real), without too much attention to the risks and negative side-effects (that are just as real). Although most police officers are enthusiastic in a general sense about these small wearable cameras, most of them have no clear ideas on how body cameras will improve policing.

I believe we have to look at bodycams more realistically, like we did with regular CCTV about ten years after that was first introduced. By now, enough research on body cameras has been done to conclude some things. First of all: bodycams are a promising technology. But, second, they do not work everywhere – the context has to be conducive to the activation of the intended mechanisms. And even if that condition is fulfilled, police officers still have to invest a lot of time and effort to make the cameras deliver the expected results.

The reality is: we don’t know much yet

I have filled up a virtual library containing 150+ publications on bodycams, published between 2004 and today. This clearly shows that we hardly know how bodycams influence the complex interactions between police and citizens. Do citizens behave differently or do police officers change their behaviour when they know they are being filmed? Or both? [1]

Policy is key

One of the things that jumps out at anyone who takes the time to read all these publications, is the fact that the policy choices or guidelines play a very important part. Three questions determine to a large extent how successful any body-cam project will be:

  • Is the use of the bodycam voluntary or mandatory?
  • Who determines what’s recorded: each police officer or general guidelines?
  • Who has access to the footage and for what purposes?

The answers will vary from place to place and there are no answers that will always produce the best results. But we do know that the answers determine for a large part, whether the bodycams will be a success.


Therefore, police and politicians have to think before they act. What choices are best for your police force, given the local circumstances and the mechanisms that you want to activate? How do your choices impact on the type of body camera you should get and the storage-solution that’s needed? How are these policy choices communicated  (training) and how will they be enforced (audits and internal sanctions). Without taking these steps, decision-makers effectively mandate practitioners to find it out for themselves. That usually does not produce the kind of focus that’s needed to have an impact on society.

A second recommendation is a call on academics to re-think the way we evaluate bodycams. It’s not interesting to publish another empirical pre/post statistic without explicitly discussing the policy-choices that were made. Only if the reader is able to compare her own police force with the one that was studied, can she determine whether the results can be generalised. As one of the most experienced researchers in the field remarked in a very recent article: “The evidence on [body cameras] is rather long on evidence and rather short on theory. Why should they ‘work’ and under what conditions or on whom?” [2]

To summarise: it would be wise to start thinking about body cameras in a more sophisticated manner in order to gain a better understanding of how and where they work. Police forces around the globe will spend millions on Body-Worn Video in the coming years. Let’s try to create the right environment for it by sharing lessons learned in different contexts.


[1] Michael White (2014), Police Officer Body-Worn Cameras; Assessing the Evidence, Washington, DC: Office of Community Oriented Policing Services. White writes: “The dynamics of police-citizen encounters are complex … The majority of studies are unable to disentangle these potential effects. Additional independent research, with rigorous methodologies, is required to substantiate these preliminary findings and to identify the underlying dynamics of behavior that are driving the noted reductions.”

[2] Barak Ariel, Alex Sutherland, Darren Henstock, Josh Young, Gabriela Sosinski (2017), ‘The Deterrence Spectrum: Explaining Why Police Body-Worn Cameras ‘Work’ or ‘Backfire’ in Aggressive Police–Public Encounters’, Policing: A Journal of Policy and Practice, pp. 1-21.

About the conference

The conference was held in Budapest from 28 thru 30 November 2017 read more.


I have rewritten this presentation into a referenced article for the peer-reviewed European Law Enforcement Research Bulletin.