Researchers studied the effect of police body-worn cameras on use of force and citizens’ complaints against the police and the results were stark:
We found that the likelihood of force being used in control conditions [no camera] were roughly twice those in experimental conditions [with a body-worn camera]. Similarly, a pre/post analysis of use-of-force and complaints data also support this result: the number of complaints filed against officers dropped from 0.7 complaints per 1,000 contacts to 0.07 per 1,000 contacts.
An order-of-magnitude drop in complaints sounds good.
Commenter Nicholas Marsh shared two explanations for the drop in complaints:
The first is that the camera wearing police are deterred from abusing their authority. The second is that members of the public are less likely to make false complaints.
If the public believe the former and police the latter there might be wide support for cameras.