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

Despite being a major social problem in the United States, there is no consensus on what constitutes a mass shooting. Historically defined as four or more people killed within 24 hours, recent studies have counted injuries and used various minimum victim thresholds. This study addresses these debates in two stages. First, a logistic regression model compares incident characteristics of 279 traditional mass shootings with at least four fatalities to 1,487 shootings with at least four injuries. Second, a multinomial logistic regression compares the characteristics of 279 mass shootings, 3,727 double firearm homicides, and 624 triple homicides. The findings indicate there are fundamental differences between these definitional criteria, and that researchers and policymakers should avoid conflating these incidents under one term.