From the January 4 edition of Fox News' The O'Reilly Factor:

GINGRICH: We are not safe. We are in much greater danger than we were a year ago, and it's not just Bush versus Obama. The North Koreans have had an additional year to build nuclear weapons and missiles. Iranians have had an additional year to develop their nuclear weapons and to keep paying for terrorists. Al Qaeda has had an additional year. And by the way, two of the top four people in Al Qaeda in Yemen were released from Guantánamo. The Obama administration continues to release terrorists back into the world --

O'REILLY: But Bush did that. Bush released those two guys. That was under the Bush administration.

GINGRICH: And then he was wrong, and the State Department was wrong in the initial releases. We now have absolute proof they're back in combat.

O'REILLY: Yeah. Yeah, they are.

GINGRICH: One estimate by the defense -- one estimate is that 74 of the released terrorists from Guantánamo have gone back to active terrorism against the United States. I think we have to confront the fact this is going to be a much bigger, much harder war than we thought it was.

Gingrich's claim originates from NY Times article that was later corrected, rebuked

Original NY Times report: “74 prisoners released from Guantánamo have returned to terrorism.” As Media Matters has noted, in the original online version of her May 20, 2009, New York Times article, Elisabeth Bumiller reported that an unreleased Pentagon report found “that about one in seven of the 534 prisoners already transferred abroad from the detention center in Guantánamo Bay, Cuba, has returned to terrorism or militant activity” and that “74 prisoners released from Guantánamo have returned to terrorism, making for a recidivism rate of nearly 14 percent” [emphasis added].

Times reporter on MSNBC: “There's some debate about whether you should say 'return.' ” As Talking Points Memo documented, the day the New York Times article was published, Bumiller said on MSNBC that "[t]here's some debate about whether you should say 'return,' because some of them were perhaps not engaged in terrorism. As we know, there are some of them being held there on vague charges."

NYT editor's note: “premise of the report that all the former prisoners had been engaged in terrorism before their detention ... remains unproved.” In an editor's note appended to the article on June 5, 2009, the Times acknowledged that the “premise of the report that all the former prisoners had been engaged in terrorism before their detention” “remains unproved,” and that the majority of the 74 detainees Bumiller cited had only been “suspected” of engaging in terrorism “without substantiation”:

A front-page article and headline on May 21 reported findings from an unreleased Pentagon report about prisoners who have been transferred abroad from the American detention center in Guantánamo Bay, Cuba. The article said that the Pentagon had found about one in seven of former Guantánamo prisoners had “returned to terrorism or other militant activity,” or as the headline put it, had “rejoined jihad.”

Those phrases accepted a premise of the report that all the former prisoners had been engaged in terrorism before their detention. Because that premise remains unproved, the day the article appeared in the newspaper, editors changed the headline and the first paragraph on the Times Web site to refer to prisoners the report said had engaged in terrorism or militant activity since their release.

The article and headline also conflated two categories of former prisoners. In the Pentagon report, 27 former Guantánamo prisoners were described as having been confirmed as engaging in terrorism, with another 47 suspected of doing so without substantiation. The article should have distinguished between the two categories, to say that about one in 20 of former Guantánamo prisoners described in the Pentagon report were now said to be engaging in terrorism. (The larger share -- about one in seven -- applies to the total number described in the report as confirmed or suspected of engaging in terrorism.)

Times public editor Hoyt rebukes article, explains that “Had only confirmed cases been considered, one in seven would have changed to one in 20.” On June 6, the Times' public editor, Clark Hoyt, wrote of Bumiller's May 20 article:

But the article on which he based that statement was seriously flawed and greatly overplayed. It demonstrated again the dangers when editors run with exclusive leaked material in politically charged circumstances and fail to push back skeptically. The lapse is especially unfortunate at The Times, given its history in covering the run-up to the Iraq war.

The article seemed to adopt the Pentagon's contention that freed prisoners had “returned” to terrorism, ignoring independent reporting by The Times and others that some of them may not have been involved in terrorism before but were radicalized at Guantánamo. It failed to distinguish between former prisoners suspected of new acts of terrorism -- more than half the cases -- and those supposedly confirmed to have rejoined jihad against the West. Had only confirmed cases been considered, one in seven would have changed to one in 20.

Most of the caveats about the report were deep in the article, where they could hardly offset the impact of the headline, the first paragraph and the prominent position on Page 1.