January 18, 2022

Research Tools: Comprehensive Database of Mass Shooters Released for Public Use

From Hamline University:

The Violence Project, a nonpartisan think tank, have publicly released the largest, most comprehensive database of mass shooters in the United States.

This new database, funded by the National Institute of Justice, the research arm of the U.S. Department of Justice, was developed by professors Jillian Peterson and James Densley and a team of students at Hamline University in St. Paul, Minnesota.  It includes 171 mass shooters from 1966 to 2019, each coded on 100 pieces of life history information. The entire database is downloadable for free at The Violence Project website.


This database is the first to look closely at the mental health histories of mass shooters. Among the 171 mass shooters, two-thirds had a mental health diagnosis or presented mental health concerns. This is only slightly higher than the fifty percent of people in the general population who will meet criteria for a mental illness in their lifetime. However, a mental health diagnosis does not mean that the actions of mass shooters are directly motivated by their symptoms. The database shows that sixteen percent of mass shootings are at least partly motivated by psychosis – which is less than the percentage that of shootings motivated by domestic issues, employment changes, interpersonal issues, and hate.

This is also the first database to look closely at how many shooters obtained their guns. The majority of mass shooters use handguns (seventy-seven percent) and twenty-five percent used assault rifles. Of the known data, seventy-seven percent of shooters purchased at least some of their guns legally, thirteen percent made illegal purchases, and nineteen percent stole guns.

Direct to Complete Announcement

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Media Coverage: Minnesota-Made Tool Tracks the How and Why Behind Mass Shootings (via Minnesota Public Radio)

About Gary Price

Gary Price (gprice@mediasourceinc.com) is a librarian, writer, consultant, and frequent conference speaker based in the Washington D.C. metro area. Before launching INFOdocket, Price and Shirl Kennedy were the founders and senior editors at ResourceShelf and DocuTicker for 10 years. From 2006-2009 he was Director of Online Information Services at Ask.com, and is currently a contributing editor at Search Engine Land.