Universal Background Checks: Shouldn't We Review the Statistics?

From all the discussion of requiring universal firearms background checks, you might assume that this is an entirely untried idea in the United States. Not at all: there are at least thirteen states that have had, for some years, some sort of mandatory background check for firearms transfers.

Six states require them for all private party transfers of firearms: California, Hawaii, Illinois, Maryland, New Jersey, and Rhode Island. Six more states have, for many years, required them for all handgun transfers: Iowa, Michigan, Nebraska, New York, North Carolina, and Pennsylvania. At least one state, Missouri, used to have such a requirement for private party handgun transfers, but repealed it in 1997.

One of the wonderful aspects of America’s experiment with federalism is that it gives us fifty laboratories, where each state can experiment with different ways of solving social problems and see what works. What troubles me about the current headlong rush towards a national universal background check requirement is how little attention we have paid to the thirteen states that have already performed the experiment.

I have recently finished a detailed paper using interrupted time series analysis of the relationship between background check laws and murder rate. This article is something of an advance warning — and yes, was conducted because a vote was coming up in Congress (and which, who knows, may come up again).

What startles from my paper’s findings is how ineffective those laws have been at what should be the most important measure: murder rate.

Of the twelve states that still have these private party background check laws, four adopted them before 1960, so the relatively consistent murder rate data from the FBI’s Uniform Crime Reports program can’t be used to test the hypothesis. Of the remaining eight, changes in murder rates are only statistically significant (at the 95% confidence interval) for five: three had an increase in murder rates after adopting mandatory background checks, two had a decrease in murder rates.

Of the three that were statistically insignificant, two states had increases in murder rates, and one had a decrease.

Interrupted time series analysis, like most bivariate correlation analysis techniques (comparing changes in two variables to see if there is perhaps a relationship), is necessarily a crude tool. I would not put enormous confidence in the results for any one state. But when nine different states, in many different years, in different regions, show a neutral to perhaps slightly negative impact on murder rates, it suggests that background check laws are either completely or at least largely irrelevant to the problem of murder.

Here’s a harsh truth: people that commit murder are not ordinary Americans, and do not obey laws. As the director of the National Institute of Justice recently observed in a leaked memo to the White House, a 2000 study found that 26% of criminal guns were stolen (often from retail stores or in transit), and 8% were the result of retail diversion by corrupt dealers. None of these criminal transactions will be affected by a background check law.

In addition, 47% of criminal guns were obtained through straw purchasers. This is already a crime, for which you can get a five-year prison sentence. But as police chiefs and U.S. attorneys admitted to the Senate Judiciary Committee a few weeks ago, they don’t have time to prosecute these straw purchasers right now. Will they have more time to prosecute people who neglect or intentionally skip the background check requirement?

Of course, the roughly one-third of murders that do not involve guns will not be affected at all.

Regarding the recent high-profile tragedies at Newtown, Aurora, Tucson, and at the Clackamas mall in Oregon: Newtown and Clackamas mall involved stolen guns from lawful owners, so a background check is irrelevant. The killers at Aurora and Tucson were both severely mentally ill — but because we decided to destroy our state mental health system in the 1970s, neither had been involuntarily committed, and so both passed the existing national background check system at dealers.

It is not enough to feel that this will make a difference; we need to make evidence-based decisions about what laws to pass. Those who refuse to do math are doomed to talk nonsense.