Conceptual Confusion: An Examination of Two Definitional Debates of Mass Shootings Using NIBRS

• In Event: Profiles & Correlates of Mass Shootings

Abstract

Objectives. Examine two definitional debates of mass shootings. First, the victim, offender, and incident characteristics of mass shootings with four or more injuries are compared to those with four or more fatalities. Second, double and triple firearm homicides are compared to “traditional” mass shootings to determine the optimal minimum victim threshold.

Methods. Utilizing information from the National Incident-Based Reporting System (NIBRS), a logistic regression model is used to compare the characteristics of injurious mass shootings (N = 1,487) and traditional mass shootings (N = 279). Meanwhile, a multinomial logistic regression model is used to compare double (N = 3,727) and triple (N = 624) homicides with mass shootings (N = 279) in the United States from 1991 to 2023.

Results. There are fundamental differences between injurious and traditional mass shootings, with the former sharing more characteristics with street gun violence, while the latter is more similar to mass murder. Furthermore, there were several significant differences between double firearm homicides and mass shootings, but few between triple homicides and mass shootings.

Conclusions. Injurious mass shootings should not be treated as the same phenomenon as traditional mass shootings. Additionally, a three or four minimum victim threshold is optimal to define mass shootings.

Author

• Kyle G. Knapp, Florida State University