Amid Shifting Legal and Political Landscapes, a New Report Highlights the Latest Findings in Gun Policy Research

There are plenty of research journals already out there. Why is the Science of Gun Policy important? And what does it add to our national conversation around gun violence and gun policy?

Around 45,000 people in the United States die from gun violence every year, and yet progress toward addressing these harms is often hindered by the polarized nature of gun policy debates. The divisiveness of US gun policy in part reflects substantial disagreement about the true effects of gun laws on a wide range of outcomes, including suicide, homicide, defensive gun use, and gun industry functioning. A key step toward implementing fair and effective gun laws is establishing a shared understanding of the effects of gun policies on a range of outcomes so that policymakers can weigh any potential trade-offs. 

The Science of Gun Policy aims to make progress on this goal by systematically and transparently assessing available scientific evidence on the effects of 18 classes of gun policies. This comprehensive resource differs from many other reviews for several reasons. 

First and foremost, it covers a wide range of outcomes and uses pre-specified criteria to gauge the methodological quality of both individual studies as well as the full body of evidence. It also restricts the included studies to those that are better suited for understanding what effects can be attributed to gun laws, as opposed to other differences between states. With both a print report and interactive website, the Science of Gun Policy highlights where evidence is strongest for potential beneficial and harmful effects of gun laws, as well as where more evidence is needed. 

In short, it helps to center science and facts in the national conversation around gun violence and gun policy. 

What is new in this third edition of the Science of Gun Policy?

Our newly released third edition expands the literature search to include studies published through 2020. This third edition of our review covers the same 18 classes of gun policies and eight outcomes as were analyzed in the second edition but includes results from two more years of published literature, so our literature search now spans a 25-year period – 1995 to 2020. In total, after reviewing thousands of candidate studies, we identified 152 that met our inclusion criteria, nearly double the number of included studies in our original review (63), and an increase of 29 studies since our second edition review.

These newly included studies allowed us to upgrade our strength of evidence ratings in several policy areas, and also helped fill in gaps for some policy areas in which we previously found no studies that met our inclusion requirements.

What are some of the key findings from the third edition of the Science of Gun Policy?

For five policies, the newly included literature increased the strength of available evidence to moderate or supportive, the two highest evidence ratings. Importantly, there is now supportive evidence that shall-issue concealed carry laws are associated with increased firearm homicides and total homicides. 

Similarly, there is now supportive evidence that child access prevention laws reduce firearm homicides and self-injuries among youth. And newly published work has also continued to support our previous edition’s conclusion that stand-your-ground laws are associated with increased levels of firearm homicides.

Overall, across the 18 classes of policies studied, only three — child-access prevention laws, shall-issue concealed carry laws, and stand-your-ground laws – had evidence of effects that met our report’s supportive rating, the highest level of evidence for a policy. Notably, these three policies all relate to how gun owners can legally store, carry, or use their firearms. And they are different from many of the other reviewed policies that primarily affect the acquisition of new firearms (such as background checks or waiting periods) or pertain to a relatively small proportion of gun owners (such as prohibitions that target domestic violence offenders).

That being said, the new evidence reviewed was sufficient for us to report a moderate evidence rating for several policy effects that we previously found to have limited or inconclusive evidence. For instance, we now conclude that there is moderate evidence that minimum age of purchase laws reduce firearm suicides among young people; that private seller background check requirements decrease total homicides; that waiting periods reduce rates of firearm suicide and total homicide; and that firearm surrender laws paired with expanded prohibitions on firearm possession (for example, by those with more serious misdemeanors) reduce firearm intimate-partner homicide.

What has changed in the field of gun policy research since the last update in 2020?

Recent and unprecedented investments in research on gun policy made by Arnold Ventures and other philanthropies, as well as by the federal government, have produced an expanding body of research in this area. For the first time, there are now approximately 100 funded gun violence prevention research projects taking place across the country. In November of 2022, the first National Conference on Firearm Injury Prevention was held which attracted more than 500 attendees, and almost 300 scientific talks and presentations. As this new crop of research and researchers matures, we can expect important new discoveries on the effects of gun policies and other gun violence prevention strategies. 

Given this growing body of evidence, what are some of the key policy recommendations from the third edition of the Science of Gun Policy?

First and foremost, our finding of supportive evidence that shall-issue laws (versus may-issue laws) are associated with increased homicides is particularly important in light of the recent Supreme Court decision in New York State Rifle and Pistol Association v. Bruen, which effectively ruled that ​“may-issue” laws violate the Second Amendment. In making decisions around concealed carry policies, states should consider the extent to which the potential harms to community safety and well-being from shall-issue laws might be mitigated through related regulation, such as requiring training or competency standards to attain a permit or through other aspects of law (for example, laws that may prevent firearm theft). 

Second, the research shows that several policies designed to limit child and adolescent firearm access may be particularly effective for reducing youth firearm-related deaths and injuries. States without child-access prevention laws should consider adopting them, especially since these types of policies also have relatively high levels of support among experts and the general public. While less strongly supported to date, increasing the minimum age to purchase a handgun may also be an effective strategy for states to consider for reducing firearm suicides. 

Third, states with stand-your-ground laws should reevaluate whether these laws are being implemented in ways consistent with the policy goal of protecting community safety and well-being. This was a recommendation from our review’s second edition, and newer studies have continued to indicate that stand-your-ground laws are associated with increased rates of total homicides and firearm homicides. While some of this increase may reflect homicides resulting from justifiable self-defense, the magnitudes of the increases appear to be too large to be explained by the increase in justifiable homicides found in studies that examined that outcome separately.

Fourth, states should consider passing laws prohibiting gun ownership while individuals are subject to domestic violence restraining orders as a strategy for reducing intimate partner homicides. While federal law has imposed this prohibition since 1994, state laws may be more effective. This may be particularly true when these prohibitions can be applied to a wide range of domestic violence cases, when the law ensures that information about the cases is included in databases used to conduct background checks, and when the prohibitions are accompanied by firearm surrender requirements.

Finally, states should consider adopting waiting period requirements and mandates for background checks on the private sale or transfer of firearms as strategies for reducing firearm homicides and suicides.