Figure. Study Flowchart of Sites and Patients Involved in Civilian Public Mass Shootings in the US, 2012-2019.

^aExcluded given atypical mechanisms of mass murder (eg, stabbing, running down individuals in vehicle) and because some individuals were not chosen indiscriminately.

^bIdentified via study site coordinators, lay press sources, and public databases.

^cIncludes 252 (62.5%) with gunshot wounds, 112 (27.8%) with other trauma, and 39 (9.7%) without physical injury. Participants were eligible if they presented to a study site hospital within 24 hours of the mass shooting and did not die in the emergency department or during initial surgery if applicable. Perpetrators were excluded.