Research on police body cameras in each of these cities in the southwest yielded encouraging results, but a number of important factors have to be kept in mind when looking at the studies.
Firstly, there are many reasons why complaints against police officers might decline other than police officers being motivated to improve their behavior. For instance, Rialto police chief Tony Farrar, who oversaw the implementation of body cameras, began his tenure shortly before the body camera study began. It is unclear how many of the use‐of‐force incidents and complaints can be attributed to body cameras improving police behavior, reforms implemented by Farrar, or other factors.
One such factor might be citizens changing their behavior in the presence of officers wearing cameras. Farrar believes that the cameras have a civilizing effect on citizens as well as police officers, “When you put a camera on a police officer, they tend to behave a little better, follow the rules a little better. […] And if a citizen knows the officer is wearing a camera, chances are the citizen will behave a little better.”
Secondly, the sample sizes are small. In Mesa, Arizona the police using the body cameras experienced a 75 percent drop in use‐of‐force complaints during the 12‐month body camera study compared to the previous 12 months. This sounds impressive, but the 75 percent represents a decline from four use‐of‐force complaints in the 12‐months prior to the evaluation to one during the trial. It would be a mistake to think that Mesa’s experiences can be expected in larger cities in different parts of the country.
Indeed, as Vezner points out, in San Diego a 12‐month body camera study revealed that there was a 10 percent increase in officer use‐of‐force incidents compared to the previous 12 months, although there was a decline in “greater controlling/defending force.” However, there was also a 23 percent drop in citizen complaints in the same time period.
It is too early to draw any definitive conclusions from the limited literature on body cameras, but this should not deter police departments and lawmakers from mandating that they be used. As I have written before, body cameras have been instrumental in investigations of police misconduct and highlighting examples of good policing. In a country where hundreds of Americans have been killed by police officers so far this year it is important that as many tools as possible are used to gather evidence for misconduct investigations.