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

New York Times columnist David Carr yesterday blasted the efficacy of the ever-growing fact-checking industry:

At any given moment during the last 18 months, there were so many truth squadrons in the air that mid-air collisions seemed a genuine possibility.

But as the campaign draws to a close, it’s clear that it was the truth that ended up as a smoldering wreck. Without getting into a long tick-tock of untruthfulness, a pattern emerged over the summer and fall: both candidates’ campaigns laid out a number of whoppers, got clobbered for doing so, and then kept right on saying them.

Brooks Jackson, director of killer site, didn’t much care for Carr’s thoughts. No way a few Web sites are going to keep politicians from stretching the truth, argues Jackson. “[T]hat’s the wrong metric,” he says via e-mail. “Any fact-checker who imagines that he or she can induce politicians to change their behavior is on a fool’s errand. And anyone who thinks that’s what we’re trying to do has jumped to the wrong conclusion.”

The real goal of fact-checking, per Jackson: “We do have evidence that we’re making voters harder to fool — and that’s our real mission.”

For that claim, Jackson cites evidence furnished by the Annenberg Public Policy Center — it’s the same group that runs, so caveat emptor. Anyhow, the group did a national telephone survey in an attempt to gauge the public’s political knowledge. One of the findings:

Of the thirty total knowledge questions asked, the sample on average answered 45.7 percent correctly. However, the responses of those who reported going to either a fact-checking website or a news website to “find out whether a statement about one of the presidential candidates was accurate or not” were more accurate than were the responses of others. Those who reported going to a fact-checking website ... answered 55.5 percent of the questions correctly, compared to 45.3 percent for those who did not go to a fact-checking website.

So there!

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.

Fourteenth: AP editor cites Bachmann fact-checking ‘quota.’

Fifteenth: Are Democrats more offended by adverse fact checks than Republicans?

Sixteenth: Fact-checking: A consumer-driven movement.

Seventeenth: Fact checkers not helping advance Obama argument.

Eighteenth: Huffington Post combines aggregation and fact-checking, unimpressively

Nineteenth: Palin calls for thorough fact-checking of Obama

Twentieth: “Obama told a whopper,” fact-checker quotes Woodward.