For questions or media comment:  Jillian Peterson, PhD, Co-founder, The Violence Project. Email:  [email protected]

New data on victims, guns, and mental health provide new insights and avenues for data-driven prevention

The Violence Project, a nonpartisan research center, has released an updated and expanded version of its popular database of mass shooters.

The Violence Project Mass Shooter Database was already the most comprehensive of its kind, with over 170 mass shooters who killed 4 or more people in a public setting since 1966 coded on 100 pieces of life history information. This update adds 50 new items for journalists, researchers, students, and policymakers to interact with.

The Violence Project Mass Shooter Database was funded by the National Institute of Justice, the research arm of the U.S. Department of Justice, and developed by professors Jillian Peterson and James Densley in collaboration with a team of students at Hamline University in St. Paul, Minnesota. The entire database is downloadable for free at www.theviolenceproject.org.

Version 2.0 of the database is being released to coincide with the one-year anniversary of the mass shootings in El Paso and Dayton, which claimed 32 lives over a 24-hour period. The database now includes names and information for all 1,215 people killed in a mass shooting since 1966—the youngest was 18 months, the oldest was 98. It also includes a new firearms database of all 377 guns used in mass shootings since 1966, individually coded by when and how they were obtained. Although two thirds were legally obtained, 30% of guns used in mass shootings came into the shooter’s possession within the month prior to being used.

The new database also includes extended information on “leakage” (communication to a third party of an intent to do harm). Most shooters who leaked their plans did so in person to their wives, coworkers, and friends, the data show. School shooters were most likely to leak their plans ahead of time and did so in every case but one.

There have been far fewer opportunities for mass shootings to occur this year with public spaces closed and people in lockdown, with only one new case in 2020—the Milwaukee Molson Coors shooting in February. However, the coronavirus pandemic has roiled the economy and exacerbated social isolation and domestic strife—all risk factors for mass shootings. Lead investigator Dr. Jillian Peterson observes, “There is a lot of pain and unmet needs right now. How we transition people back to school and work is crucial if we are to avoid more tragedy.”

Over 80% of mass shooters were in a noticeable crisis prior to their shooting. The new database breaks down that crisis into its component parts, like increased agitation, isolation, mood swings, and paranoia. The role of psychosis in mass shootings is also better accounted for. Psychosis directly motivated a mass shooting in 11% of cases, but 70% of the time, psychosis played no role at all. In 19% of mass shootings, psychosis played some role, but the shooter had other motives.

Other new items include a history of domestic violence (33% of perpetrators), a measure of firearm proficiency (higher proficiency was correlated with more deaths), violent video game playing, hate group association, childhood socioeconomic status, past school performance, community involvement, and information on siblings (mass shooters were most likely to be youngest children).

Click here to access the updated and expanded Violence Project Mass Shooter Database.

What’s new in Version 2?

• 2 new cases
• Leakage
  • How plans were leaked
  • Who plans were leaked to
  • Specific or unspecific plans
• Crisis
  • Timeline of crisis
  • Recent or ongoing stressors
  • Notably depressed mood
  • Unusually happy or calm
  • Inability to perform daily tasks
  • Rapid mood swings
  • Increased agitation
  • Abusive behavior
  • Isolation
  • Losing touch with reality
  • Paranoia
• Victims
  • Victim name
  • Victim age
  • Victim gender
  • Victim race
  • Victim relationship to shooter
• Firearms
  • Make and model
  • Classification
  • Caliber
  • Was it used in the shooting?
  • Was it modified?
  • Extended magazine?
  • When was it obtained?
  • How was it obtained (legal / illegal / gifted)
  • Prior interest in firearms
  • Firearms proficiency
• Violence
  • History of domestic violence
  • Previous sex offense
  • Use of violent video games
• Mental health
  • Mental health treatment – mandatory or voluntary
  • Mental health treatment within six months of the shooting
  • Family history of mental illness
• Family
  • Childhood socioeconomic status
  • Birth order
  • Number of siblings (older / younger)
• Other
  • Performance in school
  • Community involvement
  • Hate group association
  • Connection to fiction or pop culture
  • Armed person on the scene
• New coding for the role of psychosis in the shooting
• New coding for location – “outside” or “place of residence”