State handgun purchaser licensing laws—which go beyond federal background checks by requiring a prospective buyer to apply for a license or permit from state or local law enforcement—appear to be highly effective at reducing firearm homicide and suicide rates, according to a new analysis of gun laws in four states from researchers at the Johns Hopkins Bloomberg School of Public Health.
The study, published online today in the American Journal of Public Health, looked at changes in gun laws in Connecticut, Missouri, Maryland, and Pennsylvania and modeled trends in firearm homicide and suicide rates for up to a 22-year period, comparing actual rates to calculated approximations of the same statistics if the firearm policies under investigation had not been enacted.
Connecticut's purchaser licensing law, enacted in 1995, was associated with a 28% decrease in firearm homicide rates and a 33% decrease in firearm suicides from 1996 to 2017. Firearm suicide rates fell 23% from 1996 to 2006 and dropped even more drastically—40.5%—from 2007 to 2017, when Connecticut increased its use of a law that allows police to temporarily remove firearms from individuals threatening to harm themselves or others.
In contrast, Missouri's repeal of its purchaser licensing law in 2007 was associated with a 47% increase in the rate of firearm homicides and a 23.5% increase in firearm suicide rates from 2007 to 2016.
The researchers also looked at two states that implemented comprehensive background check laws for handguns that did not include purchaser licensing requirements. Maryland's implementation of comprehensive background check laws in 1996 was associated with a 17.5% increase in firearm homicide rates from 1997 to 2013. The law was not linked with significant changes in firearm homicide rates outside of Baltimore City. Maryland's background check requirements were associated with a 15% decline in firearm suicides; however, nonfirearm suicides also declined.
The study did not examine Maryland's purchaser licensing law, enacted in 2013, as there were too few years of post-implementation data available.
Pennsylvania enacted a comprehensive background check law in 1996 which was associated with a 21.5% increase of firearm homicide rates and a non-significant change in firearm suicides. Like Maryland, it did not have a purchaser licensing requirement during the study period.
The findings contribute to a growing body of evidence that purchaser licensing with comprehensive background checks is a highly effective policy for reducing gun-related deaths.
"So much of the gun policy discussion focuses on background checks alone," says lead author Alex McCourt, assistant scientist with the Center for Gun Policy and Research in the Department of Health Policy and Management at the Bloomberg School. "We need to recognize that background checks are necessary for identifying people prohibited from accessing a firearm, but, unless complemented by licensing, our research indicates they are not sufficient to reduce gun fatalities."
Federal law requires that a prospective buyer undergo a background check if they purchase a firearm, but only if they purchase it from a licensed dealer. Twenty-two states have extended this requirement to apply to private firearm transfers. Nine of these states, including Connecticut, Hawaii, Iowa, Illinois, Maryland, Massachusetts, New Jersey, New York, and North Carolina, and the District of Columbia have passed laws that require prospective buyers to first obtain a license or permit-to-purchase, at least for handguns.
Each state is different, but states with such licensing laws typically require gun buyers to apply for a license with a state or local law enforcement agency, pass a background check, submit fingerprints, and, in some cases, show evidence of gun safety training. Use of an applicant's fingerprints allows law enforcement to more accurately identify an individual's prior convictions or other prohibiting conditions that might otherwise be missed. States with licensing laws typically have more thorough processes for checking backgrounds, allow law enforcement more time to conduct those checks, and/or have mandatory waiting periods.
For the study, the researchers compared four statistics—firearm homicide, nonfirearm homicide, firearm suicide, and nonfirearm suicide rates—in the four selected study states to the same statistics in synthetic control states—modeled states created to reflect what would have happened if a state did not adopt comprehensive background checks and/or purchaser licensing laws during the same time period.
The study periods for each state were determined by the amount of data available following the law change and the state's policy landscape. The researchers looked at Pennsylvania data from 1985-2017, Maryland data from 1985-2013, Missouri data from 1997-2016, and Connecticut data from 1985-2017.
Using the Centers for Disease Control and Prevention's annual mortality data from 1985-2017, the researchers calculated the percent change in homicides and suicides, both with and without involvement of a firearm, between the state with the policy of interest and its synthetic control.
The study also found that for purchaser licensing laws, rates of homicides and suicides that did not involve firearms did not change significantly in Connecticut relative to its synthetic control. In Missouri, there was an 18% increase in nonfirearm homicide rates associated with the repeal of the state's handgun purchaser licensing law and no significant change in nonfirearm suicide rates. The significant increase in nonfirearm homicide in Missouri suggests that factors other than the law's repeal may have contributed to rising homicide rates from 2008-2016.
The researchers found that following the implementation of comprehensive background check laws, Maryland saw a 33% increase in nonfirearm homicide rates and a 22% decrease in nonfirearm suicides relative to the control states. In Pennsylvania, nonfirearm homicide rates were 10% lower than the synthetic control and the state saw a 12% decrease in nonfirearm suicides.
The study also examined if homicide increases in Maryland and Pennsylvania might be partially explained by factors unique to large cities. When Baltimore was excluded from the Maryland analysis, comprehensive background check laws were not associated with significant changes in either firearm or nonfirearm homicides, suggesting that increases in state homicide rates may have been specific to Baltimore. Unlike Maryland, however, firearm homicide and nonfirearm homicide rates increased when Philadelphia data was excluded from the Pennsylvania models.
The researchers suggest that, in addition to adding licensing requirements, comprehensive background check laws can be more effective by more robustly enforcing the laws to promote compliance, broadening prohibiting conditions, improving recordkeeping, and expanding the time to complete the background checks.
"Purchaser licensing has an extremely strong evidence base and research has consistently found protective effects on a range of issues," says co-author Cassandra Crifasi, deputy director of the center. "These laws also have broad public support among Americans, including the majority of gun owners. States looking to advance evidence-based policies to reduce gun violence should consider a purchaser licensing law."