From the August 29 Washington Post article, headlined, “How a Detainee Became An Asset: Sept. 11 Plotter Cooperated After Waterboarding”:

After enduring the CIA's harshest interrogation methods and spending more than a year in the agency's secret prisons, Khalid Sheik Mohammed stood before U.S. intelligence officers in a makeshift lecture hall, leading what they called “terrorist tutorials.”

[...]

These scenes provide previously unpublicized details about the transformation of the man known to U.S. officials as KSM from an avowed and truculent enemy of the United States into what the CIA called its “preeminent source” on al-Qaeda. This reversal occurred after Mohammed was subjected to simulated drowning and prolonged sleep deprivation, among other harsh interrogation techniques.

[...]

The debate over the effectiveness of subjecting detainees to psychological and physical pressure is in some ways irresolvable, because it is impossible to know whether less coercive methods would have achieved the same result. But for defenders of waterboarding, the evidence is clear: Mohammed cooperated, and to an extraordinary extent, only when his spirit was broken in the month after his capture March 1, 2003, as the inspector general's report and other documents released this week indicate.

Article reported that Mohammed said he “gave a lot of false information ... in order to make the ill-treatment stop”

From the August 29 Washington Post article:

Mohammed, in statements to the International Committee of the Red Cross, said some of the information he provided was untrue.

“During the harshest period of my interrogation I gave a lot of false information in order to satisfy what I believed the interrogators wished to hear in order to make the ill-treatment stop. I later told interrogators that their methods were stupid and counterproductive. I'm sure that the false information I was forced to invent in order to make the ill-treatment stop wasted a lot of their time,” he said.

Article reported that the CIA IG did not “reach definitive conclusions about the effectiveness of particular interrogation methods”

CIA inspector general: Report did not analyze “the use of particular techniques with particular individuals and independently confirm the quality of the information that came out.” The Post reported that “John L. Helgerson, the former CIA inspector general who investigated the agency's detention and interrogation program, said his work did not put him in 'a position to reach definitive conclusions about the effectiveness of particular interrogation methods.' ” Helgerson added: “Certain of the techniques seemed to have little effect, whereas waterboarding and sleep deprivation were the two most powerful techniques and elicited a lot of information. ... But we didn't have the time or resources to do a careful, systematic analysis of the use of particular techniques with particular individuals and independently confirm the quality of the information that came out.” [Washington Post, 8/29/09]

IG report conclusion: “The effectiveness of particular interrogation techniques in eliciting information that might not otherwise have been obtained cannot be so easily measured.” The report stated that the CIA's “detention and interrogation of terrorists has provided intelligence that has enabled the identification and apprehension of other terrorists and warned of terrorist plots planned for the United States and around the world.” But, the report added that the “effectiveness of particular interrogation techniques in eliciting information that might not otherwise have been obtained cannot be so easily measured.” [May 7, 2004, CIA inspector general report on “counterterrorism detention and interrogation activities,” page 100]

Recently released CIA memos don't discuss EITs. Several media outlets have noted, as The New York Times did, that the partially declassified versions of two recently released CIA memos do not contain reference “to any specific interrogation methods and do not assess their effectiveness.” Newsweek reported that “the newly declassified material does not convincingly demonstrate” that “the agency's use of 'enhanced interrogation techniques' -- including sleep deprivation, stress positions, violent physical contact, and waterboarding” was what “produced ... useful information” that detainees provided. The article added that “though two of the newly released CIA reports offer examples of the kind of details that detainees surrendered, the reports do not say what information came as a result of harsh interrogation methods and what came from conventional questioning.”

Other media note that IG report is not conclusive of the effectiveness of controversial interrogation techniques

Bush terrorism adviser Frances Townsend: The report “doesn't say that” the CIA obtained “the most critical information after techniques had been applied.” Townsend stated: “It's very difficult to draw a cause and effect, because it's not clear when techniques were applied vs. when that information was received. It's implicit. It seems, when you read the report, that we got the ... most critical information after techniques had been applied. But the report doesn't say that.” [CNN's Anderson Cooper 360, 8/25/09]

ABC News: CIA documents do not “indicate” whether valuable “information was obtained as a result of controversial interrogation techniques, such as waterboarding. ” ABCNews.com reported that documents related to the 2004 CIA IG report “back up the Bush administration's claims that intelligence gleaned from captured terror suspects had thwarted terrorist attacks, but the visible portions of the heavily redacted reports do not indicate whether such information was obtained as a result of controversial interrogation techniques, such as waterboarding.” [ABCNews.com, 8/25/09]

Los Angeles Times: Documents offer “little to support the argument that harsh or abusive methods played a key role.” The article reports that the CIA documents “are at best inconclusive” as to the EITs' effectiveness and offer “little to support the argument that harsh or abusive methods played a key role.” [Los Angeles Times, 8/26/09]