Examining the impact of external influences on police use of deadly force over time.

Prior deadly force research has sought to identify appropriate mechanisms that can effectively control police officers' decisions to use deadly force. However, the relative impact of external discretion control policies on police shooting behavior remains largely unknown. Using data from Philadelphia for a period of more than two decades, this article employs interrupted time-series analysis (ARIMA) to examine the impact of legislation and judicial intervention on use of deadly force by Philadelphia police officers. The article also considers the impact of larger, community-level characteristics on levels of deadly force. Findings produced modest support for the potential effect of external discretion control policies and community-level factors on police shooting behavior but generally suggest that dynamic changes in the internal working environment can outweigh the influence of the external mechanisms.