Over the last year this newspaper has shone the bright light of hindsight on decisions that led the United States into Iraq. We have examined the failings of American and allied intelligence, especially on the issue of Iraq's weapons and possible Iraqi connections to international terrorists. We have studied the allegations of official gullibility and hype. It is past time we turned the same light on ourselves.

In doing so - reviewing hundreds of articles written during the prelude to war and into the early stages of the occupation - we found an enormous amount of journalism that we are proud of. In most cases, what we reported was an accurate reflection of the state of our knowledge at the time, much of it painstakingly extracted from intelligence agencies that were themselves dependent on sketchy information. And where those articles included incomplete information or pointed in a wrong direction, they were later overtaken by more and stronger information. That is how news coverage normally unfolds.

But we have found a number of instances of coverage that was not as rigorous as it should have been. In some cases, information that was controversial then, and seems questionable now, was insufficiently qualified or allowed to stand unchallenged. Looking back, we wish we had been more aggressive in re-examining the claims as new evidence emerged - or failed to emerge.

The problematic articles varied in authorship and subject matter, but many shared a common feature. They depended at least in part on information from a circle of Iraqi informants, defectors and exiles bent on "regime change" in Iraq, people whose credibility has come under increasing public debate in recent weeks. (The most prominent of the anti-Saddam campaigners, Ahmad Chalabi, has been named as an occasional source in Times articles since at least 1991, and has introduced reporters to other exiles. He became a favorite of hard-liners within the Bush administration and a paid broker of information from Iraqi exiles, until his payments were cut off last week.) Complicating matters for journalists, the accounts of these exiles were often eagerly confirmed by United States officials convinced of the need to intervene in Iraq. Administration officials now acknowledge that they sometimes fell for misinformation from these exile sources. So did many news organizations - in particular, this one.

Some critics of our coverage during that time have focused blame on individual reporters. Our examination, however, indicates that the problem was more complicated. Editors at several levels who should have been challenging reporters and pressing for more skepticism were perhaps too intent on rushing scoops into the paper. Accounts of Iraqi defectors were not always weighed against their strong desire to have Saddam Hussein ousted. Articles based on dire claims about Iraq tended to get prominent display, while follow-up articles that called the original ones into question were sometimes buried. In some cases, there was no follow-up at all.

On Oct. 26 and Nov. 8, 2001, for example, Page 1 articles cited Iraqi defectors who described a secret Iraqi camp where Islamic terrorists were trained and biological weapons produced. These accounts have never been independently verified.

On Dec. 20, 2001, another front-page article began, "An Iraqi defector who described himself as a civil engineer said he personally worked on renovations of secret facilities for biological, chemical and nuclear weapons in underground wells, private villas and under the Saddam Hussein Hospital in Baghdad as recently as a year ago." Knight Ridder Newspapers reported last week that American officials took that defector - his name is Adnan Ihsan Saeed al-Haideri - to Iraq earlier this year to point out the sites where he claimed to have worked, and that the officials failed to find evidence of their use for weapons programs. It is still possible that chemical or biological weapons will be unearthed in Iraq, but in this case it looks as if we, along with the administration, were taken in. And until now we have not reported that to our readers.

On Sept. 8, 2002, the lead article of the paper was headlined "U.S. Says Hussein Intensified Quest for A-Bomb Parts." That report concerned the aluminum tubes that the administration advertised insistently as components for the manufacture of nuclear weapons fuel. The claim came not from defectors but from the best American intelligence sources available at the time. Still, it should have been presented more cautiously. There were hints that the usefulness of the tubes in making nuclear fuel was not a sure thing, but the hints were buried deep, 1,700 words into a 3,600-word article. Administration officials were allowed to hold forth at length on why this evidence of Iraq's nuclear intentions demanded that Saddam Hussein be dislodged from power: "The first sign of a `smoking gun,' they argue, may be a mushroom cloud."

Five days later, The Times reporters learned that the tubes were in fact a subject of debate among intelligence agencies. The misgivings appeared deep in an article on Page A13, under a headline that gave no inkling that we were revising our earlier view ("White House Lists Iraq Steps to Build Banned Weapons"). The Times gave voice to skeptics of the tubes on Jan. 9, when the key piece of evidence was challenged by the International Atomic Energy Agency. That challenge was reported on Page A10; it might well have belonged on Page A1.

On April 21, 2003, as American weapons-hunters followed American troops into Iraq, another front-page article declared, "Illicit Arms Kept Till Eve of War, an Iraqi Scientist Is Said to Assert." It began this way: "A scientist who claims to have worked in Iraq's chemical weapons program for more than a decade has told an American military team that Iraq destroyed chemical weapons and biological warfare equipment only days before the war began, members of the team said."

The informant also claimed that Iraq had sent unconventional weapons to Syria and had been cooperating with Al Qaeda - two claims that were then, and remain, highly controversial. But the tone of the article suggested that this Iraqi "scientist" - who in a later article described himself as an official of military intelligence - had provided the justification the Americans had been seeking for the invasion.

The Times never followed up on the veracity of this source or the attempts to verify his claims.

A sample of the coverage, including the articles mentioned here, is online at nytimes.com/critique. Readers will also find there a detailed discussion written for The New York Review of Books last month by Michael Gordon, military affairs correspondent of The Times, about the aluminum tubes report. Responding to the review's critique of Iraq coverage, his statement could serve as a primer on the complexities of such intelligence reporting.

We consider the story of Iraq's weapons, and of the pattern of misinformation, to be unfinished business. And we fully intend to continue aggressive reporting aimed at setting the record straight.

To the Editor:

"The Times and Iraq" (From the Editors, May 26) says, "Articles based on dire claims about Iraq tended to get prominent display, while follow-up articles that called the original ones into question were sometimes buried."

It seems to me that despite the fact that it is "From the Editors," this is a follow-up article of the most essential sort.

So if you really wanted to be "aggressive" at "setting the record straight," perhaps you should have taken your own advice and started this very refreshing acknowledgment above the fold on Page A1.

NILS JOHNSON-SHELTON
Brooklyn, May 26, 2004

To the Editor:

"The Times and Iraq" is a watershed journalistic event, demonstrating that candor and forthrightness applied to the turning of the "accountability spotlight" on oneself do not beget perceptions and judgments of weakness from the outside but rather perceptions of unusual strength and confidence.

I applaud The New York Times and can only hope that your extraordinary action here serves as a model for our country's institutions to follow as they consider their future responsibilities to, and communications with, the American people.

STEPHEN ZIMNEY
New York, May 26, 2004

To the Editor:

The Times reports, with insufficient embarrassment, that it has been snookered for more than two years on the subject of Iraq by the Bush administration.

There must be a lesson here somewhere. Perhaps it is this: Don't believe anything this administration says unless it can be independently verified.

The instinct to jump into print should have been constrained by the responsibility to check the facts. Instead, The Times found itself used, consciously or not, as a Bush propaganda organ to drum up support for the Iraq war.

ROGER LIPPMAN
Seattle, May 26, 2004

To the Editor:

Your admission that The Times's reporting on intelligence claims about prewar Iraq was insufficiently skeptical is welcome. But it is disappointing that you had to wait until Ahmad Chalabi fell from grace with the United States government before you acknowledged the dubious nature of his information and your reporters' overdependence on him.

STEVEN SHERMAN
Chapel Hill, N.C., May 26, 2004

To the Editor:

The Times's self-critique reminded me of how let down I have felt by the press and Congress since the administration started beating its war drums two years ago.

It already seemed obvious then that any connection between Iraq and 9/11 was a stretch and that the neoconservatives' dream of planting democracy in the Mideast was wishful thinking at best, dangerously delusional at worst.

Is it also wishful thinking to believe that if the press and Congress had done their jobs - challenged the bullies in the White House instead of succumbing to their spin - history might have played out differently?

ANNE TRAVERS
Montclair, N.J., May 26, 2004

To the Editor:

I'm troubled by what you leave out of your editors' article about The Times's reporting during the prelude to war in Iraq.

You talk about what The Times did wrong, but not why or what you're going to do about it.

The Times was guilty of credulous and biased reporting. How do you account for that?

It's not enough to point to your reliance on bad informants. There will always be bad informants. How will you try to prevent such credulous reporting in the future?

VICKI O'DAY
Menlo Park, Calif., May 26, 2004

To the Editor:

Good for you, New York Times, for acknowledging that your writers were less than thorough in ascertaining all the facts leading up to the war in Iraq and in its aftermath. I admire your courage in publicly admitting to errors in judgment and your lack of aggressiveness in challenging the accepted wisdom of questionable sources, including the White House. One can only wish the president would follow your courageous lead.

TERI SHERIDAN
New York, May 26, 2004

To the Editor:

I am a faithful Times reader, but I don't know quite what to think about your editorial confession. Somehow, I doubt that many will find it comforting.

Perhaps if you and other news organizations had shone a brighter light on George W. Bush and Dick Cheney before the last presidential election, we would have no Iraq war to report on today at all.

DEBORAH FREEDMAN
Hamden, Conn., May 26, 2004

To the Editor:

When I read "The Times and Iraq," I thought: Not good enough. You're The New York Times.

Those of us in the air-conditioned wilderness with our minds still intact need your eyes - accurate and each morning.

Failure and self-flogging won't unspill the blood in Iraq.

Getting the truth every day, on each piece, is an impossibly high standard. But it is the mark of The New York Times. Back to work.

JON BELL
Tucson, May 26, 2004

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