Twenty years later: The Federal Assault Weapons Ban curtailed public mass shootings (Preprint)

Abstract

Assault weapon and large capacity magazine bans are potential tools for policymakers to prevent public mass shootings. However, the efficacy of these bans is a continual source of debate. In an earlier study, we estimated the impact of the Federal Assault Weapons Ban (FAWB) on the number of public mass shooting events. This study provides an updated assessment with three additional years of firearm surveillance data to characterize the longer-term effects.

To estimate the impact of the FAWB on trends in public mass shootings from 1966 to 2022.

We use linear regression to estimate the impact of the FAWB on the five-year simple moving average of annual, public mass shootings, defined by events with four or more deaths in a 24-hour period, not including the perpetrator. The study period spans 1966 to 2022. The model includes indicator variables for both the period of the FAWB (1995-2004) and the period after its removal (2005-2022). These indicators were interacted with a linear time trend. Estimates controlled for the national homicide rate. After estimation, the model provided counterfactual estimates of public mass shootings if (1) the FAWB were never imposed and (2) if the FAWB remained in place.

The overall upward trajectory in the number of public mass shootings substantially fell while the FAWB was in place. These trends are specific to events in which the perpetrator used an assault weapon or large capacity magazine. Estimates suggest the FAWB prevented five public mass shootings while the ban was active. A continuation of the FAWB/LCMB would have prevented up to thirty-eight public mass shootings.

The FAWB, which included a ban on large capacity magazines, was associated with fewer public mass shooting events, fatalities, and nonfatal gun injuries. Gun control legislation is an important public health tool in the prevention of public mass shootings.

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