High-profile mass shootings and recent spikes in violent crime have revitalized the discussion over gun control in the United States. While Americans disagree on many gun policies, background checks have drawn bipartisan support. But do they work?

SPA Professor Janice Iwama attempts to answer this question in “Reducing Violence?: Examining the Impact of Gun Control Legislation in Massachusetts” (Justice Quarterly, October 2021), by examining the impact of the state’s 2014 background check and licensing legislation on violent crimes. While her findings did not indicate a reduction in violent crime, they do provide important implications for states crafting gun control policy.

“Massachusetts attempted to fill the loophole [left by the Brady Act], through a statewide system that says, in order for you to purchase a firearm, you need to get a state license,” explained Iwama. “That state license requires you to undergo a background check” conducted by a licensing authority. The state also requires that customers purchasing firearms at gun shows undergo a background check and any firearm sold by a private dealer or given as a gift must be registered in the state’s system.

While the 1993 Brady Act, which requires federally-licensed dealers to run background checks on prospective customers, remains the only federal-level legislation, 13 states have introduced and passed their own policies. However, the impacts of gun legislation can be difficult to isolate and measure, so few empirical studies exist on their effectiveness. For example, while passage of the Brady Act met with a slight decrease in the crime rate, according to some studies, other factors may have contributed, including the decade’s tough focus on crime, the war on drugs, and increased police budgets. Also, background check policies can vary significantly by state, and few maintain the appropriate data.

So-called red flag laws, under which certain parties may request that local authorities remove an otherwise-legal firearm from an owner who may harm themself or others, are also difficult to evaluate. The acceptable party varies by state, and can include parents, significant others, and/or medical doctors.

In addition, it is impossible to calculate the number of guns in circulation: official numbers only represent the number of times a federally-licensed dealer runs a background check.

“If I were to walk in and purchase 20 firearms, they would still only run one background check,” said Iwama. “The picture of how many firearms actually exist is not very accurate.”

This scarcity of data makes Iwama’s study especially distinct. Since 2006, Massachusetts has collected data on gun purchases and licensing across all 14 counties; Iwama obtained a dataset, stretching from 2006-2016, from its Firearms Records Bureau, on licensing, sales by gun dealers, private transfers of weapons, and denials due to criminal histories, mental health records, fugitive status, and other factors.

Without these numbers, and the proper impact assessment, even states with recent gun control legislation are unable to determine their effectiveness, much less identify and close loopholes in the policy. One such loophole, said Iwama, is uneven enforcement.

“We believe, if we pass a law, that every county, every city, is going to enforce it evenly,” she said. “The reality is that doesn't happen.” Massachusetts’s legislation, a response to the 2012 Sandy Hook shootings, became law in 2015, but it took even longer to reach some jurisdictions. Even then, police chiefs soon realized the extent of their discretion to deny licensing applications based on informal knowledge, and applied that discretion at different levels across the state.

“The ability to actually get some data at the county level saying ‘this is the percentage of statutory disqualifications we've seen, and this is the percentage of denials for this type of discretion’ allowed me to better control for that uneven level of enforcement,” Iwama added.

However, selective enforcement and time constraints still limited the findings. The data, which stopped just one year after the legislation took effect, showed no significant impact on most crime rates, including aggravated assault, rape, or murder. Robbery, shortly after the passage of the legislation, did show a slight increase (7-8%). Iwama hopes to collect more recent data and conduct more long-term research, to better control for irregularities in enforcement. In addition, privacy laws prevent the legislation from working as intended, by shrouding mental health history records, especially those in private hospitals.

“We find that, for the most part, people who are engaged in gun violence and the unique instances of a mass shooting generally have a mental health history, or some type of background or criminal record that got missed,” said Iwama. “We have to think carefully about how we create this legislation and identify and close loopholes. What about people who are obtaining firearms from private dealers, or through friends, or through parents?”

Geographical proximity to other states also presents a problem, according to law enforcement agencies.

“States as small as Massachusetts mean a lot of folks travel to and from other states with looser laws, like Vermont, Connecticut, Rhode Island, and New Hampshire, purchase a firearm, and come back to the state,” she explained.

Iwama credits these state-level irregularities with the push for federal gun control, but fears that other legislative priorities will distract advocates in Congress. Meanwhile, she hopes that new state-level legislation will mean more, and richer, data on gun ownership.

“As a researcher, I hope to get better data,” she said. “When you pass legislation, make sure you tie it to an evaluation. Make sure you add a clause that lets us assess how effective this is, in reality.”

In addition to long-term analyses of the impact of the Massachusetts law, Iwama’s future research will consider distinctions between the behaviors of those who own one gun, purchased for safety concerns, and those who own multiple firearms, or collectors.

“People who own two or more firearms are really just collectors,” she said. “It's the people who are purchasing firearms, thinking it's a public safety thing, hearing a knock on the door, and using that firearm, that is dangerous.”

This pursuit of hard data, she argues, could help establish middle ground in the highly-polarized public debate on gun policy, by reassuring concerned responsible gun owners. She urges the public to consider these same nuances, instead of retreating behind pro- and anti-gun propaganda.

“Gun control legislation is not taking guns away from legally-abiding citizens; it's trying to prevent future crime and keeping firearms out of the hands of individuals with a history of violence or mental health issues,” she said. “You can still have your right, but you have to go through a process, similar to obtaining a driver's license. [The data is] an illustration of the fact that this legislation is not affecting citizens like yourself.”