Do gun laws have an effect on gun violence?  This is one of the most debated questions related to gun policy and efforts to reform or tighten existing gun laws.  As a result, this topic has been researched extensively from everyone from medical researchers to epidemiologists, to public health experts, to economists.  The answer to the question is a resounding “yes.”  There is undoubtedly a relationship between laws and policies related to firearms and the frequency, rate, and lethality of gun violence.

Below are a number of academic research studies and publications related to gun permits (shall issue and may issue), right to carry laws, and laws requiring a permit in order to purchase a firearm.

Tennessee is a right-to-carry, shall-issue state.

Right-to-Carry Laws and Violent Crime: A Comprehensive Assessment Using Panel Data and a State-Level Synthetic Controls Analysis
John J. Donohue, Abhay Aneja, Kyle D. Weber
Journal of Empirical Legal Studies (2019)
Key Findings: Right-to-carry (RTC) laws are associated with higher aggregate violent crime rates, and the size of the deleterious effects that are associated with the passage of RTC laws climbs over time.  Violent crime in RTC states was estimated to be 13 to 15 percent higher – over a period of 10 years – than it would have been had the state not adopted the law.

Easiness of Legal Access to Concealed Firearm Permits and Homicide Rates in the United States
Michael Siegel MD, MPH, Ziming Xuan ScD, SM, MA, Craig S. Ross PhD, MBA, Sandro Galea MD, DrPH, MPH, Bindu Kalesan PhD, MPH, MSc, Eric Fleegler MD, MPH, and Kristin A. Goss PhD, MPP
Journal of American Health (2017)
Key findings: Shall-issue laws were significantly associated with 6.5% higher total homicide rates, 8.6% higher firearm homicide rates, and 10.6% higher handgun homicide rates, but were not significantly associated with long-gun or nonfirearm homicide. Shall-issue laws are associated with significantly higher rates of total, firearm-related, and handgun-related homicide.

Association Between Connecticut’s Permit-to-Purchase Handgun Law and Homicides
Kara E. Rudolph PhD, MPH, MHS, Elizabeth A. Stuart PhD, Jon S. Vernick JD, and Daniel W. Webster ScD, MPH
American Journal of Public Health (2015)
Key findings: It is estimated that the law was associated with a 40% reduction in Connecticut’s firearm homicide rates during the first 10 years that the law was in place. By contrast, there was no evidence for a reduction in nonfirearm homicides. Consistent with prior research, this study demonstrated that Connecticut’s handgun permit-to-purchase law was associated with a subsequent reduction in homicide rates. As would be expected if the law drove the reduction, the policy’s effects were only evident for homicides committed with firearms.

Effects of the Repeal of Missouri’s Handgun Purchaser Licensing Law on Homicides
Daniel Webster, Cassandra Kercher Crifasi, and Jon S. Vernick
Journal of Urban Health (2014)
Key findings: Using death certificate data available through 2010, the repeal of Missouri’s permit-to-purchase (PTP) law was associated with an increase in annual firearm homicides rates of 1.09 per 100,000 (+23 %) but was unrelated to changes in non-firearm homicide rates. Using Uniform Crime Reporting data from police through 2012, the law’s repeal was associated with increased annual murders rates of 0.93 per 100,000 (+16 %). These estimated effects translate to increases of between 55 and 63 homicides per year in Missouri.