Study: Body Cameras Massively Reduce Police Use of Force

Well, this is a chin-scratching result from a recent study:

Wearing body cameras increases assaults against officers and does not reduce police use of force

….Averaged over 10 trials, [body cameras] had no effect on police use of force, but led to an increased rate of assaults against officers wearing cameras.

More accurately, this would be a chin-scratching result if it were true. But even though this is directly from the journal article, it’s a wildly misleading headline. Here are the details:

The researchers set out a protocol for officers allocated cameras during the trials: record all stages of every police-public interaction, and issue a warning of filming at the outset….Researchers found that during shifts with cameras in which officers stuck closer to the protocol, police use-of-force fell by 37% over camera-free shifts. During shifts in which officers tended to use their discretion, police use-of-force actually rose 71% over camera-free shifts.

Yikes! For officers who kept the cameras rolling all the time, use-of-force fell 37 percent. That’s not just huge, it’s positively gargantuan. Use-of-force only increased among officers who turned their cameras on and off. In other words, the real headline result is: keep the cameras rolling all the time and use-of-force plummets. So why on earth does the headline suggest that body cameras have no effect? In fact, their effect ranges from -37 percent (rolling all the time) to zero (control groups) to +71 percent (cameras on and off). That’s gigantic beyond belief.

As for the 15 percent increase in assault against officers, that’s very weird. It’s a big increase, and apparently no one has a good idea of what might have caused it. I wonder if they also got different results here depending on whether officers followed the protocol and kept their cameras on at all times?

Bottom line: these results are too big. I don’t have access to the paper, but something has to be going on. It’s hardly believable that body cameras truly have an effect this gigantic. Something went wrong with this study.

UPDATE: It turns out there were two separate papers involved. Details here.