How do Body-Worn Cameras Affect Officer Behaviour? A Quasi-Experimental Analysis.

This thesis analyses the impact of the Detroit Police Department’s adoption of body-worn cameras (BWCs) on complaint-adjudication outcomes and officer proactivity. By exploiting the staggered implementation of the technology by precinct, I estimate the effect of BWCs on the probability of allegations being sustained, the number of officer-initiated encounters, 911 response times, and time spent on scene. In a city shaped by previous federal oversight and institutional reform, I find that BWCs are associated with a substantial and statistically significant increase in the probability of officers being exonerated, particularly for demeanour-, service-, and procedure-related allegations. The results provide limited support for the “civilizing effect” hypothesis, suggesting instead that BWCs primarily served as exculpatory evidence in complaint adjudication. Moreover, while BWCs appear to be associated with a reduction in officer-initiated encounters, driven by a decline in the volume of traffic stops, I find little evidence in favour of the “de-policing hypothesis”: response times were unaffected and on-scene time increased slightly, with the greatest change observed in investigations, which are among the most discretionary policing activities. Finally, I argue that previous policing reforms may have rendered the role of BWCs more marginal.