Citation

DiMaggio C, Avraham J, Berry C, Bukur M, ScD JF, Klein M, Shah N, Tandon M, Frangos S. J. Trauma Acute Care Surg. 2019; 86(1): 11-19.

Affiliation

New York University School of Medicine, Department of Surgery, Division of Trauma and Critical Care Surgery.

Copyright

(Copyright © 2019, Lippincott Williams and Wilkins)

DOI

10.1097/TA.0000000000002060

PMID

30188421

Abstract

BACKGROUND: A federal assault weapons ban has been proposed as a way to reduce mass shootings in the U.S. (U.S). The Federal Assault Weapons Ban (A.W.B.) of 1994 made the manufacture and civilian use of a defined set of automatic and semi-automatic weapons and large capacity magazines illegal. The ban expired in 2004. The period from 1994 to 2004 serves as a single-arm pre-post observational study to assess the effectiveness of this policy intervention.

METHODS: Mass shooting data for 1981 to 2017 were obtained from three well-documented, referenced, and open-source sets of data, based on media reports. We calculated the yearly rates of mass shooting fatalities as a proportion of total firearm homicide deaths and per U.S. POPULATION: We compared the 1994-2004 federal ban period to non-ban periods, using simple linear regression models for rates and a Poison model for counts with a year variable to control for trend. The relative effects of the ban period were estimated with odds ratios.

RESULTS: Assault rifles accounted for 430 or 85.8% of the total 501 mass-shooting fatalities reported (95% CI 82.8, 88.9) in 44 mass-shooting incidents. Mass shootings in the U.S. accounted for an increasing proportion of all firearm-related homicides (coefficient for year = 0.7, p = 0.0003), with increment in year alone capturing over a third of the overall variance in the data (Adjusted R-squared = 0.3). In a linear regression model controlling for yearly trend, the federal ban period was associated with a statistically significant 9 fewer mass shooting related deaths per 10,000 firearm homicides (p = 0.03). Mass-shooting fatalities were 70% less likely to occur during the federal ban period (Relative Rate = 0.30, 95% CI 0.22,0.39).

CONCLUSIONS: Mass-shooting related homicides in the U.S. were reduced during the years of the federal assault weapons ban of 1994 to 2004. STUDY TYPE: Observational LEVEL OF EVIDENCE: III/IV.

Language: en