When no one is watching: evaluating the impact of body-worn cameras on use of force incidents

Abstract

ABSTRACT Outcomes associated with police body-worn cameras (BWCs) and their influence on use of force is chiefly known from large-scale implementation studies and randomised controlled trials. While these studies provide valuable insight, there is concern that these studies are susceptible to the Hawthorne effect. Using an interrupted time series analysis, this study examines whether the implementation of BWCs had an effect on use of force incidents within a United States department that independently adopted BWCs and did not participate in a collaborative research trial. Results show that while there was a non-significant drop in use of force incidents at the month of BWC implementation, there was a steady, significant increase in use of force incidents for every month following implementation. The number of incidents reaches pre-BWC implementation frequencies after three years. These findings indicate that BWCs may influence police behaviour immediately following implementation, though this influence weakens over time as BWCs become normalised with daily police use.