Gun researcher and FoxNews.com columnist John Lott is ignoring the evidence in an attempt to undermine claims from supporters of strengthening gun laws that a large percentage of guns are purchased without the buyer undergoing a background check.

In a National Review Online article, Lott wrote that President Obama's recent claim that “as many as 40 percent of guns are purchased without a background check” is false, instead stating that “it closer to 10 percent.” However, research shows that significant numbers of firearms are in fact sold without a background check - perhaps a figure greater than the 40 percent cited by Obama.

It is true that the 40 percent figure is based on a 1994 poll with a small survey sample, and that the authors of the study have said that they estimated that the actual figure for gun sales from private sellers ranges from 30 to 40 percent of all sales. But no data has been compiled that contradicts that figure, while several more recent data points support a figure in that range.

In finding that the “40 percent” statistic is “Mostly True,” Politifact pointed out that neither the National Rifle Association nor the National Shooting Sports Foundation, groups that oppose expanding background checks to private sales, provided data contradicting that figure.

As Washington Post fact checker Glenn Kessler reported, part of the problem in obtaining up-to-date figures on the private sales of firearms is that National Rifle Association lobbyists have been successful in convincing Congress to block funding for such research. In his analysis of the 40 percent figure, Kessler quoted one of the authors of the 1994 study, Jens Ludwig, who stated, “While there is no perfect estimate in social science, we'd have a better estimate for this proportion had the federal government not decided to get out of the business of supporting research on guns and gun violence several years ago.”

But the data that has been made available since the 1994 report lends credence to that estimate. For example, a 2012 analysis of how handguns are sold in Michigan, the Michigan State Police reported that 48 percent of all handguntransfers in the state are conducted through private sales where no background check is required. Criminals in particular tend to seek weapons from sources where they are not subject to background checks - only 11 percent of inmates incarcerated for gun crimes said that they got the weapon from a licensed gun dealer, according to a 2004 survey.  

Data from the gun industry itself also suggests sales without a background check are commonplace. According to 2010 data from the National Shooting Sports Foundation, only 45 percent of assault weapon owners reported buying their firearm from a retail location, including independent and chain retail stores. Approximately half of respondents reported buying their firearm from venues where a background check is not necessarily required, including over the Internet, from gun shows, or through a face-to-face sale.

Lott, who has been discredited as a gun researcher by serious academics and has been caught modifying his research when his conclusions are called into question, deceptively interprets data in his NRO article. For example, one of the criticisms that Lott offers against the 1994 survey is that some gun buyers who went to a “kitchen table” type dealer “had no inkling that the dealer was actually 'licensed,' ” incorrectly assuming that only “brick and mortar” stores were licensed dealers. Thus, Lott argues, the survey is flawed and the numbers are exaggerated. But for his assumption to be true, it would mean that the mistaken gun purchasers forgot that they filled out the ATF Form 4473; a document that licensed dealers required their customers to complete where the purchaser attested that he or she was not prohibited from buying a firearm.

Lott also launches a secondary attack on background checks, by claiming that the vast majority of the approximately 150,000 background check denials that occur each year are false positives where the purchaser is not actually prohibited from buying a firearm. He does this by making the absurd assumption that because only 62 people in one year were prosecuted for lying on a form to buy guns, every other background check failure was a false positive.

In fact a comprehensive analysis from The Washington Post suggests that the vast majority of individuals denied by the background check system are actual prohibited purchasers. The FBI, which in 2010 was responsible for approximately half of all denials, reported that less than five percent of denials were successfully appealed. The primary reasons for denial were a felony conviction or indictment (47.4 percent) or status as a fugitive (19.1 percent).