Academic Studies on the Effects of Laws and Policies on Gun Violence

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 the effect of laws and policies on gun violence.


Right-to-Carry Laws and Violent Crime: A Comprehensive Assessment Using Panel Data and a State-Level Synthetic Controls Analysis
John J. Donohue, Abhay AnejaKyle 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
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.

Firearm Prevalence and Homicides of Law Enforcement Officers in the United States
David I. Swedler PhD, MPH; Molly M. Simmons AB, Francesca Dominici PhD; David Hemenway PhD
American Journal of Public Health (2015)
Key findings: High public gun ownership is a risk for occupational mortality for law enforcement officers in the United States. States could consider methods for reducing firearm ownership as a way to reduce occupational deaths of law enforcement officers.

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
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.

The Relationship Between Gun Ownership and Firearm Homicide Rates in the United States, 1981–2010 
Michael Siegel; Craig S. Ross; Charles King III
American Journal of Public Health (2013)
Key findingsGun ownership was a significant predictor of firearm homicide rates (incidence rate ratio = 1.009; 95% confidence interval = 1.004, 1.014). This model indicated that for each percentage point increase in gun ownership, the firearm homicide rate increased by 0.9%. There is a robust correlation between higher levels of gun ownership and higher firearm homicide rates. States with higher rates of gun ownership had disproportionately large numbers of deaths from firearm-related homicides.

State-level homicide victimization rates in the US in relation to survey measures of household firearm ownership, 2001–2003
Matthew Miller, MD, MPH; ScD, Deborah Azrael, MS, PhD; David Hemenway, PhD
Social Science & Medicine (2007)
Key findings: States with higher rates of household firearm ownership had significantly higher homicide victimization rates of men, women and children. Study findings suggest that the household may be an important source of firearms used to kill men, women and children in the United States.

Rates of Household Firearm Ownership and Homicide Across US Regions and States, 1988–1997
Matthew Miller, MD, MPH; ScD, Deborah Azrael, MS, PhD; David Hemenway, PhD
American Journal of Public Health (2002)
Key findings: In region- and state-level analyses, a robust association between rates of household firearm ownership and homicide was found. Regionally, the association exists for victims aged 5 to 14 years and those 35 years and older. At the state level, the association exists for every age group over age 5, even after controlling for poverty, urbanization, unemployment, alcohol consumption, and nonlethal violent crime. In areas where household firearm ownership rates were higher, a disproportionately large number of people died from homicide. 

Shooting Down the More Guns, Less Crime Hypothesis
Ian Ayres, John J. Donohue III
National Bureau of Economic Research
Key findings: In most states, shall-issue laws have been associated with more crime and that the apparent stimulus to crime tends to be especially strong for those states that adopted in the last decade.


State Gun Laws, Gun Ownership, and Mass Shootings in the US: Cross Sectional Time Series
British Medical Journal (2019)
States with more permissive gun laws and greater gun ownership had higher rates of mass shootings, and a growing divide appears to be emerging between restrictive and permissive states.

Firearm Laws and Firearm Homicides
A Systematic Review
Journal of the American Medical Association (2017)
Lois K. Lee, MD, MPH; Eric W. Fleegler, MD, MPH; Caitlin Farrell, MD; Elorm Avakame, BS; Saranya Srinivasan, MD; David Hemenway, PhD; Michael C. Monuteaux, ScD
Key findings: The strength of firearm legislation in general, and laws related to strengthening background checks and permit-to-purchase in particular, is associated with decreased firearm homicide rates. High-quality research is important to further evaluate the effectiveness of these laws.

State Intimate Partner Violence–Related Firearm Laws and Intimate Partner Homicide Rates in the United States, 1991 to 2015
Carolina Díez, BA; Rachel P. Kurland; Emily F. Rothman, ScD; Megan Bair-Merritt, MD, MSCE; Eric Fleegler, MD, MPH; Ziming Xuan, ScD, SM, MA; Sandro Galea, MD, DrPH, MPH; Craig S. Ross, PhD, MBA; Bindu Kalesan, PhD, MPH, MSc; Kristin A. Goss, PhD, MPP; Michael Siegel, MD, MPH
Annals of Internal Medicine (2017)
Key FindingsState laws that prohibit persons subject to intimate partner violence-related restraining orders from possessing firearms and also require them to relinquish firearms in their possession were associated with 9.7% lower total intimate partner homicide (IPH) rates (95% CI, 3.4% to 15.5% reduction) and 14.0% lower firearm-related IPH rates (CI, 5.1% to 22.0% reduction) than in states without these laws.

What Do We Know About the Association Between Firearm Legislation and Firearm-Related Injuries?
Julian Santaella-Tenorio, Magdalena Cerdá, Andrés Villaveces, Sandro Galea
Epidemiologic Review (2016)
Key findings: Specific laws combining different types of firearm regulations are the best way to reduce deaths from gun violence. Some specific regulations – such as background checks – are the most effective.   

Firearm legislation and firearm mortality in the USA: a cross-sectional, state-level study
Dr Bindu Kalesan, PhDMatthew E Mobily, MDOlivia Keiser, PhDJeffrey A Fagan, PhDSandro Galea, MD
The Lancet (2016)
Key findings: Very few of the existing state-specific firearm laws are associated with reduced firearm mortality, and this evidence underscores the importance of focusing on relevant and effective firearms legislation. Implementation of universal background checks for the purchase of firearms or ammunition, and firearm identification nationally could substantially reduce firearm mortality in the USA.

Effects of Policies Designed to Keep Firearms from High-Risk Individuals
Daniel W. Webster and Garen J. Wintemute
Annual Review of Public Health
Key findings: Mounting evidence indicates that certain laws intended to increase the accountability of firearm sellers to avoid risky transfers of firearms are effective in curtailing the diversion of guns to criminals, in particular the more rigorous permit-to-purchase (PTP) handgun laws, comprehensive background checks, strong regulation and oversight of gun dealers, and laws requiring gun owners to promptly report lost or stolen firearms. Evidence that lower levels of guns being diverted to criminals will translate into less gun violence is less robust, but it appears that rigorous PTP handgun laws are protective against homicides and suicides

Effect of Gun Culture and Firearm Laws on Gun Violence and Mass Shootings in the United States: A Multi-Level Quantitative Analysis
Frederic Lemieux
International Journal of Criminal Justice Sciences
Key findings:
The quantitative analyses points out that both cultural and legislative proposition have significant impacts on deaths by guns. While the cultural explanation seems to be related to an increase in deaths by gun, the legislative perspective is associated with a decrease in deaths by gun and mass shootings. These results show that a reduced firepower capacity- fewer firearms and therefore a lesser capacity to fire – is clearly associated with fewer victims. This result is true no matter what type of weapon is used by the shooters. In other words, the limitation of ammunition capacity saves lives more than targeting specific models of weapons. In the case of the semi-automatic assault rifle, the limitation of ammunition defeats the purpose of these weapons as a direct consequence. Another finding shows that a majority of shooters (56%) clearly had known mental illness and at lower percentage had domestic violence history or were involved in an intense divorce/custody battle. This result points out critical elements of stability to be assessed during background check procedures.  In addition to criminal records, relevant mental health information and known background information by law enforcement should be included into the verification process to limit the access of firearms to at risk individuals based on these cumulative factors. Nevertheless, legislators should keep in mind that these numbers prove that more restrictive gun regulations will save lives above and beyond the issue of spontaneous mass shootings and can counterbalance the deadly effects of a violent gun culture.

Firearm Legislation and Firearm-Related Fatalities in the United States
Eric W. Fleegler, MD, MPH; Lois K. Lee, MD, MPH; Michael C. Monuteaux, ScD; David Hemenway, PhD; Rebekah Mannix, MD, MPH
Journal of the American Medical Association (2013)
Key Findings: A higher number of firearm laws in a state are associated with a lower rate of firearm fatalities in the state, overall and for suicides and homicides individually.

Legal Status and Source of Offenders’ Firearms in States with the Least Stringent Criteria for Gun Ownership
Katherine A Vittes, Jon S. Vernick, Daniel Webster
Journal of Injury Prevention (2013)
Key Findings: Stricter gun ownership laws would have made firearm possession illegal for many state prison inmates who used a gun to commit a crime.  Requiring all gun sales to be subject to a background check would make it more difficult for these offenders to obtain guns.


Frozen Funding on Firearm Research: “Doing Nothing Is No Longer an Acceptable Solution”
Marian E. Betz
, MD, MPH, Megan L. Ranney, MD, MPH, and Garen J. Wintemute, MD, MPH
Western Journal of Emergency Medicine (2016)
Key conclusion: We need research to know what works to prevent firearm injury, when, with whom, and how. We must not lose sight of the larger goal of increasing federal support for firearm violence research, but we also must not lose time waiting for the money to appear before we take action. Our patients and our communities deserve safety.