A systematic review by the Campbell Collaboration identified 30 studies (experimental and quasi-experimental) on the use of Body Cameras that measured the behavior of police officers and citizens. The results varied widely, but there are indications that Body Cameras can be effective to reduce the number of complaints against police officers, with a 16.6% reduction in complaints [1]. However, the results did not show a consistent impact on reducing the use of force, indicating a 6.8% reduction, which is of little statistical significance. Analyses suggest that restrictions on police officers’ freedom of choice to turn on the camera can reduce the use of force, but further studies are needed.
With regard to the effects on aggression against police officers, injuries caused by them, and resistance to police approaches, the same meta-analysis reported a small (15.9%) increase in aggression or resistance to those wearing cameras. However, this result was not statistically significant.
A second systematic review updated the meta-analytical dataset used in the aforementioned study, adding two Randomized Controlled Trials (RCTs) [2]. This new review supported the hypothesis that Body Cameras can affect both the use of force by the police and the number of complaints filed by citizens against police officers. The average effect on those two areas was -9.6% and -16.9%, respectively. However, although the estimated impact on the use of force was 40% higher than that presented in the first systematic review, the authors themselves warn that this result is not considered statistically significant either, according to the levels conventionally accepted in statistical studies.