U.S. flag

An official website of the United States government, Department of Justice.

Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.


Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Sources of Data Used in 44 Analyzed Studies on Mass Shootings


Secondary data comprises news accounts, literature, previous research data sets, monographs, books, advocacy groups, international sources, press data sets, internet, and other sources. Official records come from the Federal Bureau of Investigation’s (FBI) Supplementary Homicide Reports (SHR), Uniform Crime Reports (UCR), National Incident-Based Reporting System (NIBRS), and other FBI sources; the Bureau of Justice Statistics (BJS); the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF); the Central Intelligence Agency’s (CIA) World Fact Book (WFB); the U.S. Department of Education’s (ED) National Center for Education Statistics (NCES); the New York Police Department (NYPD) and other police records; courts; and other sources.