Public Mass Shootings: Database Amasses Details of Half Century of U.S. Mass Shootings

Persons who engaged in U.S. public mass shootings over the last half century were commonly troubled by personal trauma before their shooting incidents, nearly always in a state of crisis at the time, and, in most cases, engaged in leaking their plans before opening fire. Most were insiders of a targeted institution, such as an employee or student. Except for young school shooters who stole the guns from family members, most used legally obtained handguns in those shootings of multiple people. This article discusses a National Institute of Justice-supported, publicly available, database that identifies common traits of persons who have engaged in public mass shootings from 1966 to 2019. The Violence Project database covers 172 mass public shooters and more than 150 psychosocial history variables, such as those individuals’ mental health history, past trauma, interest in past shootings, and situational triggers. The aim is to build a broader understanding on the part of the public, the justice system, and the research community of who mass shooters are and what motivates their decision to discharge firearms at multiple people.