Gun Law Debates Rest on Weak Scientific Evidence, Research Says

A person holds a gun in a file image. (Scott Olson/Getty Images)

Debates on gun laws have heated up again following recent mass shootings and crime surges, but neither side has strong scientific evidence to fall back on, according to RAND Corporation.

In a newly released report, RAND researchers suggest several statistical models to more effectively measure the effects of state gun laws, based on a years-long rigorous review.

After reviewing 12,916 relevant studies published between 1995 and 2018, RAND researchers identified just 123 studies that were properly designed to show a causal relationship between gun laws and subsequent effects.

Poorly designed studies often equate a correlational relationship with a causal relationship, such as claiming a state’s gun law decreased crime by simply comparing it to crime in other states without such a law.

Numerous other factors, such as changes in policing or social investment, could have also been in play. Quality studies do best to explain away alternative factors, according to the report.

RAND researchers used Royal Society of Medicine guidelines during the review process.

A total of 18 gun laws and eight outcomes were examined.

After examining those 123 studies that met the threshold, researchers found inconclusive evidence that restrictive gun laws have any impact on mass shootings or unintentional injuries and deaths.

As for violent crime, there is inconclusive evidence that low-quality handgun bans, assault weapon and high-capacity magazine bans, and licensing and permitting laws have any impact.

Researchers did find limited evidence that concealed-carry laws contributed to violent crime.

Limited evidence means at least one study without serious methodological problems shows the link.

Some of the 123 studies still contain serious methodological weaknesses, according to the study.

They also found moderate evidence that background checks decreased firearm homicides.

Moderate evidence means two or more studies—at least one without serious methodological weakness—show the link, and no studies show otherwise.

The strongest evidence was found in child-access prevention laws, which several studies found have decreased firearm suicides and unintentional injuries and deaths.

RAND researchers also wanted to evaluate gun law effects on defensive gun use, and hunting or recreational activities, but found almost zero such studies.

They urge more studies to be done in this regard.

“Effective gun policies in the United States must balance Second Amendment rights and public interest in gun ownership with concerns about public safety,” an earlier RAND gun policy report says.

RAND Corporation launched its Gun Policy in America Initiative in 2016, with a goal to establish shared facts to inform the public and support fair and effective gun policies.

Recently, RAND surveyed 173 experts nationwide about their views on the probable effects of gun laws.

As expected, the experts fell into two groups, those who favor more-permissive regulatory approaches to gun access and those who favor more-restrictive approaches.

However, they do agree on one policy: to prosecute those who cannot legally own a gun, but through illegal means get one anyway.