Red flag laws may reduce the growing burden of firearm homicides

August 28, 2028-- A recent study from researchers at Columbia University Mailman School of Public Health found that Florida’s red flag gun law, which was enacted in response to the 2018 Parkland mass shooting, was associated with an 11 percent reduction in firearm homicide rates from 2019 to 2021. Firearm homicides are a leading cause of death among those under 44 in the U.S. and Florida’s red flag law allows law enforcement officers to temporarily remove firearms from individuals deemed a danger to themselves or others. This is among the first research to link firearm legislation in the U.S. with a significant decrease in gun-related homicides. The findings are published in JAMA.

The researchers used mortality data from CDC WONDER on firearm and non-firearm homicide and suicide mortality and employed augmented synthetic control methods. These methods constructed a proxy state for Florida from 19 politically conservative states without similar gun laws during the study period, allowing for a counterfactual comparison in mortality rates in the post-law enactment period from 2019 to 2021. Models also controlled for state-level sociodemographic and economic covariates.

The researchers found that Florida’s firearm homicide rate increased from 4.51 deaths per 100,000 population in 2017 to 5.28 in 2021, compared to 4.50 to 6.85 for its proxy state. Models estimated that by 2021, Florida’s firearm homicide rates were significantly lower than expected, which translated to a reduction of 0.73 fewer deaths per 100,000 individuals per year on average in the post-law enactment period. Findings were not significant, however, for other mortality outcomes across the post-law enactment period.

“Our study underscores the complexities of reducing firearm mortality through legislative measures in the U.S. While the observed reduction in firearm homicide rates following the enactment of Florida’s red flag law is promising, further research is needed to understand the broader effectiveness of such policies,” said Catherine Gimbrone, MPH, in the Department of Epidemiology at Columbia Mailman School, and first author.  “In particular, we did not observe a significant average reduction in firearm suicides, another critical public health issue in the U.S. This finding further emphasizes the need for continued research to fully assess the impact of firearm legislation.”

The researchers also point out that Florida’s response to the COVID-19 pandemic might have differed from control states in ways that affected firearm homicides. Nonetheless, they adjusted for covariates in their analysis that they believe may have resulted in spurious associations. Additionally, Gimbrone, who is also a doctoral student in the Psychiatric Epidemiology Training Program, cannot definitively attribute the reduction in expected firearm homicide rates to the red flag law compared to other societal changes after Parkland. However, findings suggest that red flag laws may reduce the growing burden of firearm homicides. 

A co-author is Kara E. Rudolph, Columbia Mailman School.

The study was supported by the National Institute of Mental Health pre-doctoral training grant 32MH013043-52.

Columbia University Mailman School of Public Health

Founded in 1922, the Columbia University Mailman School of Public Health pursues an agenda of research, education, and service to address the critical and complex public health issues affecting New Yorkers, the nation and the world. The Columbia Mailman School is the fourth largest recipient of NIH grants among schools of public health. Its nearly 300 multi-disciplinary faculty members work in more than 100 countries around the world, addressing such issues as preventing infectious and chronic diseases, environmental health, maternal and child health, health policy, climate change and health, and public health preparedness. It is a leader in public health education with more than 1,300 graduate students from 55 nations pursuing a variety of master’s and doctoral degree programs. The Columbia Mailman School is also home to numerous world-renowned research centers, including ICAP and the Center for Infection and Immunity. For more information, please visit www.mailman.columbia.edu.