Contagious fire? an empirical assessment of the problem of multi-shooter, multi-shot deadly force incidents in police work

Recent police shootings in which multiple officers fired numerous rounds at suspects have led some observers to assert that such situations involve "contagious fire," where an initial officer's shots launch a cascade of gunfire from other officers present. Although there is anecdotal recognition of the contagious fire phenomenon among police and the media, there is not a single empirical study documenting its existence in more than 50 years of deadly force research. This article uses Philadelphia Police Department shooting data to explore the potential for police shootings to become contagious. The article provides a testable definition of contagious shootings and identifies predictors of three outcomes: multiple officer shootings, the average number of shots fired per officer, and multi-officer, multi-shot incidents. Findings show that the requisite preconditions for a contagious shooting rarely occur, and when the preconditions were met, there is no evidence to support the existence of a contagion effect.