Last week, we reported that John Lott, a former University of Chicago visiting assistant professor and conservative media pundit, wrongly accused Media Matters of misquoting him. In fact, after we accurately quoted a post Lott had written, Lott's post mysteriously changed, making it appear we had misquoted him, when we had not.

The switch was picked up by Paul Krugman at The New York Times, who wrote:

So, it appears that Lott retroactively tried to put his original statement down the memory hole, then accused a critic of wronging him by quoting what he originally said. Now, that's scholarship!

Brad DeLong, a professor of economics at the University of California at Berkeley, also impugned Lott's apparent dishonesty.

But Lott's shoddy scholarship last week wasn't just limited to this incident. He also pushed a new version of his factually challenged claim that the National Instant Background Check System (NICS) -- which is used to determine if someone is legally allowed to purchase a gun -- is highly inaccurate, writing:

Over 99.9 percent of purchases initially flagged as being illegal under the law were “false positives” - law-abiding citizens incorrectly identified as banned individuals.

Take the numbers for 2008, the latest year with data available. The 78,906 initial denials resulted in only 147 cases involving banned individuals trying to purchase guns being referred to prosecutors. Of those 147 cases, prosecutors thought the evidence was strong enough to prosecute only 105, and they won convictions in just 43. But few of these 43 cases involved career criminals or those who posed real threats. The typical case was someone who had a misdemeanor conviction for an offense he didn't realize prevented him from buying a gun.

Lott has previously disregarded our debunking of his flawed analysis, so we contacted Ronald Fransen, the researcher whose report Lott cites to justify his “99.9%” conclusion. Frandsen told us the data does not back up Lott's “analysis.” Yesterday Frandsen emailed Media Matters:

You asked me if it was accurate for an article to state that “Over 99.9percent of purchases initially flagged as being illegal under the [Brady] law were 'false positives' - law-abiding citizens incorrectly identified as banned individuals.” That statement cannot be supported by statistics on Brady Act background checks that have been collected since 1999.

A person whose firearm transfer application is denied by a background check pursuant to the Brady Act may appeal the denial. Statistics on appeals of denials have been collected since 1999 in a series of publications entitled Background Checks for Firearm Transfers, and are summarized in Trends for Background Checks for Firearm Transfers, 1999-2008. During that ten year period, nearly 1.5 million firearm transfer applications were denied and nearly 237,000 of those denials were appealed. Over 86,000 appeals resulted in a reversal of the denial, which would calculate to about 6% of the 1.5 million denials. Some of the reversals may have occurred because a person was mistakenly identified as being prohibited; however, no data is available on the reasons for reversals.

The URL for Trends for Background Checks for Firearm Transfers, 1999-2008 is http://www.ncjrs.gov/pdffiles1/bjs/grants/231187.pdf. [Emphasis added]

Lott's apparent disregard for scientific rigor, creation of a fake internet persona and allegations that he fabricated survey results have been documented (here, here, here, here, here and here). Despite this checkered past Lott continues to publish on foxnews.com, recently appeared on Fox Business News' Freedom Watch, and was called in for a wild-eyed anti-Obama screed at Big Government, where his post mysteriously changed.

We are still waiting to hear anything explaining Lott's mysteriously changing quote, until then we will just add this and his factually challenged data analysis as yet more demonstrations that Lott isn't a credible source of information, no matter how many times right wing media features his commentary.

EDITORS NOTE (4/5/2011):

The photo of John Lott has been changed.