The truth-challenged Republican primary candidate. (Jae C. Hong/AP)

Fourteenth in a series of endless, tireless, exhaustive, hairsplitting, obsessive, resounding, never-before-attempted and conclusive posts on the fact-checking industry.

In a panel of fact-checking all-stars this morning at the National Press Club, a predictable question arose: What about the studies that have shown that fact-checking operations are tougher on Republican than Democratic politicians?

Among the points raised by the panel was that the balance over the past year has been skewed by the barroom brawl also known as the Republican primary season. A lot of nodding ensued.

Jim Drinkard, an Associated Press (AP) editor who oversees the wire service’s fact-checking work, said, “We had to have a self-imposed Michele Bachmann quota in some of those debates.”

After the session, Drinkard said that there wasn’t an actual numerical quota on Bachmann at the AP. It’s just that if the AP had gone back and vetted all her claims that looked dicey, the result would “overload” the debate story. “Often she was just more prone to statements that just didn’t add up,” said Drinkard.

One of those statements was the famous instance in which she told the “Today” show that the HPV vaccine can have “very dangerous side effects.”

Moving on to other AP fact-checking issues, Drinkard said he had no involvement in the much-cited and denounced AP piece that mentioned the Monica Lewinsky scandal in fact-checking a claim by former President Bill Clinton at the Democratic National Convention.

The Fact-Checking series so far:

First: Can you remind me again what this fact-check debate is about?

Second: Is Fox really fact-checking the first lady’s claim that her husband is open-minded?

Third: CNN says fact-checking squares with its exclusive spot in cable-news sphere.

Fourth: Clinton bedevils fact-checkers.

Fifth: Fox’s Cavuto slights fact-checking of Clinton speech, perhaps including Fox’s fact-checking of Clinton speech.

Sixth: Fact-checking IS the substance that news consumers have been asking for.

Seventh: Biden and Obama keep checkers busy.

Eighth: A task for fact-checkers: Did the administration apologize for American values?

Ninth: Fact-checkers take dim view of Romney “apology” claims.

Tenth: GOP lawmaker says he doesn’t care what a fact-checker says.

Eleventh: Soledad O’Brien says she’s “required” to fact-check

Twelfth: Romney’s not-so-secret comments take a beating from checkers

Thirteenth: Catch the error in this Washington Times invite.