This policy brief discusses gun control and mass shootings, based on the authors’ recent empirical study that focused on a specific type of mass shooting, i.e., those that occur in public settings.
The study first reviews definitions of mass shootings and then discusses issues related to identifying the effects of gun control measures. This report concludes with a discussion of the effects of gun control measures and implications gun control holds for future public policy. The definition of “mass public shooting” used in this study is “an incident in which four or more victims are fatally shot in a public location within a 24-hour period in the absence of other criminal activity, such as robberies, drug deals, and gang conflict.” The study accessed a comprehensive list of mass public shooting incidents and victim counts in the United States from 1976-2018, along with a database of 89 state gun laws with transparent definitions that the authors had compiled. This improves on previous work that used limited data on both mass shootings and gun laws. The study identified 156 unique mass public shootings with 2,839 victims shot, 1,090 of whom died. One set of data analyses assessed the influence of laws on the incidence of mass public shootings, and another set assessed the influence of relevant law on the severity of mass public shootings in terms of victim counts. The research findings are consistent with previous similar studies, which suggest that 1) requiring a permit to purchase or possess a gun may reduce the incidence of mass public shootings; and 2) banning large-capacity magazines may reduce the number of victims when such a shooting occurs.