The Effects of ERPOS on Mass Public Shootings: Insights from Staggered Difference-in-Differences Estimation

• In Event: Profiles & Correlates of Mass Shootings

Abstract

Extreme Risk Protection Orders (ERPOs) are a relevant but understudied policy that empower legal authorities to confiscate firearms from individuals at risk of harming themselves or others. While ERPOs have been enacted in 21 states, our understanding of their effects remains underdeveloped, particularly for mass public shootings. Therefore, we examined the likelihood that ERPOs are associated with an increase or decrease in mass public shooting incidents at the state level. Using the Situational Mass Shooting Database (SMSDB), we examined 416 mass public shooting incidents aggregated across 1,600 state-years (50 states x 32 years) from 1991 to 2022. Staggered differences in differences estimation revealed that, on average, the implementation of ERPO policies is associated with a 2.31% decrease in the rate of mass public shootings across treated states compared to control states. While the annual reductions in mass shootings associated with ERPOs may seem small, their cumulative long-term impact could be substantial in preventing tragedies.

Authors

• Brynn Schuetter, University of South Carolina

• Brent Klein, University of South Carolina

• Emily Greene-Colozzi, University of Massachusetts Lowell

• Jaclyn Schildkraut, Rockefeller Institute of Government, SUNY Albany