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How The Media Covered The Lancet Study

A surprising inability to convey the study’s findings accurately

For Stats.org at George Mason University, Robert Lichter, Ph.D., writes:
A new study has generated heavy news coverage with its finding that over 650,000 Iraqis have died as a direct or indirect result of the March 2003 US-led invasion. It has also created widespread controversy, largely because this total is far higher than any previous estimate, which creates political problems for President Bush and other supporters of the war. The study, which appeared in the British medical journal The Lancet, is a follow-up to a previous study that attracted similar criticism.

Surprisingly, however, some leading news outlets both here and abroad have proved unable to correctly state the major findings. Extrapolating from a randomly-based survey of Iraqi households, the researchers estimated that approximately 655,000 Iraqis had died as a result of the war, including 601,000 whose deaths involved some form of violence. These two numbers are the core of the current debate.

These figures were prominently displayed both in the article and in the press release sent out by the Lancet. Yet some major news organizations somehow failed to get them straight.

Most prominent among them was the New York Times, which headlined its article, "Iraqi dead may total 600,000, study says." Of course that number was 55,000 too low, because it referred only to the violent deaths.

One might argue that this error did not materially influence the basic message of the story. In fact it was echoed by other major papers such as the Wall Street Journal: "Iraqi death toll exceeds 600,000, study estimates," the Los Angeles Times: "study puts wars Iraqi death tally at more than 600,000." and the Financial Times: "conflict in Iraq has killed more than 600,000 people."

All the above headlines are literally correct. They are just misleading, because they are nearly 10 percent too low, and they clearly reflect confusion between the study’s two separate estimates. But the Washington Post inverted this mistake in a front-page teaser referring readers to a story on an inside page: "a new study says 655,000 more Iraqis have died violently [emphasis added] since the invasion than otherwise would have been killed." Ironically, the story itself got the numbers right. But readers who glanced at the front page got the impression that the study’s estimate of violent deaths was over 50,000 higher than the actual figure.

However, the lead sentence in the New York Times article contained a much more significant blooper than appeared in any of the other papers: "A team of American and Iraqi public health researchers has estimated that 600,000 civilians have died in violence across Iraq since the 2003 American invasion... [emphasis added] The error was compounded later in the article, which described last July as "the highest [month] for Iraqi civilian deaths since the American invasion."

This is a glaring error, because it vastly increases the number of the war’s innocent victims, making the conflict seemed even more terrible than it already is. Moreover, the researchers were quite clear about having counted all deaths rather than civilian deaths. For example, they noted that almost 60 percent of deaths occurred among military-age men. In fact it is probably impossible to reliably separate civilian from combatant deaths. Many Iraqis surveyed would be highly unlikely to admit that their deceased family members had been involved in military activity, either because they were fighting with the insurgents or because they were fighting for the Iraqi security forces but sought to hide this information from the insurgents.

Because this error appeared in the New York Times, it was picked up by other papers subscribing to the Times news service, appearing as far away as the San Francisco Chronicle and the Times of India. But foreign media didn’t need the New York Times to confuse the total death toll with the civilian death count. For example, Der Spiegel, the Time magazine of Germany, headlined its story, "new study estimates 600,000 civilian Iraqi death toll." the Sydney, Australia morning Herald led with: "More than 600,000 civilians have died in violence across Iraq since the 2003 US invasion..." And Al Jazeera managed to combine the errors made by both the New York Times and the Washington Post: "More than 650,000 Iraqi civilians have died in violence as a result of the US-led 2003 invasion of Iraq, a new study says..."

What makes these errors particularly egregious is that the same authors, using the same methods, published earlier findings from this research project only two years ago, in October 2004. They reached the same conclusion, that the number of Iraqi deaths attributable to the war was far higher than any previous estimate. Finally, their report produced the same sort of controversy that has recurred this month. You might expect, therefore, that some of the world’s leading news organizations would be at an advantage in reporting the facts this time around. But you would be wrong. To make these mistakes the second time around recalls an Oscar Wilde character’s criticism of an orphan: "To lose one parent... may be regarded as a misfortune; to lose both looks like carelessness."

UPDATE: The Rich Are Different

A Hedge Fund Manager's Family Values

Broward-Palm Beach News reports:

After publishing Kelly Cramer's remarkable story "Daddy's Girl" two weeks ago, the most frequent question I've been asked about the tale of a Wall Street millionaire who married his own daughter is: How could Linda Schutt, a grown woman with a PhD in psychology, succumb to the seduction attempts of her father, hedge-fund manager Bruce McMahan, and participate in a years-long incestuous relationship with him?

Setting aside the curious notion that people don't seem nearly as puzzled by a filthy-rich financier sleeping with his own spawn, I have to admit that the question is a good one. Watching Linda in her video deposition, portions of which we made available on our website, browardpalmbeach.com, she appears to be telling the truth; she comes off as someone who was genuinely victimized. But we also published her e-mails, and in some of them, she sounds pretty enthusiastic about bedding her own dad.

Let me refresh your memory. Just a few days after their June 2004 "wedding" at Westminster Abbey, Bruce e-mailed: "Miss you W. Think nasty things about you all the time." Linda responded promptly, also using their cute abbreviations for husband and wife: "Mmm yeah, nasty is so good. You must have read my mind. What else can we say, we're H & W — that's the beauty."

Yes, eww. And for the lawyers among you, let me point out that those e-mails were entered as exhibits in a court document.

But getting back to our question: What was it about Linda that allowed her to participate in this kind of behavior? Oddly, a possible answer to that question may have come from Linda's half-sister, Heather McMahan, who jumped to the defense of her family's honor in a story in the New York Post last week.

"[Linda] was a very sexual person, like most McMahans tend to be. We have a pretty strong libido — all of us," Heather told the Post in a story in which she went on to describe her beloved half sis as a sexual freak show. At a party, for example, Heather said that Linda turned a goodbye peck into a Girls Gone Wild moment.

"She put her hands on both my cheeks and goes right for my mouth," Heather told the Post. "I pulled back, and she said: 'Wait a minute. If you don't let me kiss you on the lips, how are you going to let me kiss you down there again?'"

Now, keep in mind Heather told these things to the Post because she wanted to convince the American public that Linda and her father would never, ever engage in an incestuous relationship.

Let's break down Heather's reasoning: Heather assures us that Linda would never sleep with Dad — and she knows this how? Because Linda made sexual come-ons to her own half sister.

I guess that's the kind of logic that makes sense only in families who control more money than the gross national product of Uganda.

The Post featured Heather in two follow-up stories to their own splashy rewrite of Cramer's story, which they plugged on page one and slapped across pages 12 and 13 of their September 28 issue. (Although dated September 28, our story actually hit our website on Tuesday, September 26.) In both Post follow-ups, Heather questioned Linda's motives and suggested that Linda was lying when she testified, under oath, about sex with her dad and the wacky wedding at England's big church. (And the Post also mentioned that Heather, 44, is a sculptor, but I don't know how the venerable tabloid resisted mentioning that her short list of film acting credits includes appearances in Class of Nuke 'Em High and The Toxic Avenger IV, in which she played a character named — I shit you not — The Vibrator.)

The Post presented Heather's accusations as news, even though Cramer, in her original story, had already pointed out that family members said they doubted Linda's story. Heather didn't return Cramer's e-mail, but older sister Alison did. Cramer's story quoted not only Alison but also Melinda Ewell, one of McMahan's ex-wives, as doubting Linda's account.

Not that those doubts matter much. Go back and read the opening of Cramer's story in which she makes the point that Linda and Bruce kept their relationship secret from the rest of the family. When the clan gathered for holiday parties, for example, Linda moved the Cartier Trinity ring Daddy had given her to a nonwedding-ring finger, for the sake of appearances.

So it's little wonder that other family members are emerging today, saying they didn't know about Bruce and Linda's naughty nuptials. They weren't invited.

According to an e-mail we received, McMahan family members are telling one another in the wake of our story that Linda made up her testimony about the Westminster Abbey ceremony. As for the photo we printed of Bruce and Linda snuggling with the Eiffel Tower in the background, the e-mailer tells us it was from "a family outing with all of the McMahans in Paris."

But rest assured, Bruce and Linda were at Westminster Abbey, posing in photos with their new wedding rings.

We have an entire series of these shots, which we were able to confirm were taken outside the Little Cloister garden at the Abbey. In our original story, we printed only the most dramatic image: the close-up of Bruce's hand on Linda's, showing off their rings. To aid those McMahans who still doubt the truth, we've reproduced some of the other photos from the happy occasion on this page.

Bruce never got around to testifying in the five lawsuits resulting from this strange case, but if he had, it would have been interesting to see him answer for these photos. If Linda is lying about the wedding ceremony, why were father and daughter posing outside Westminster Abbey with expensive wedding rings on their ring fingers?

Bruce made sure he would never have to answer those and other uncomfortable questions. (Like, for example, what his sperm cells were doing on a vibrator encrusted with dried bodily fluids, pubic hairs, and skin cells that turned out to match Linda's DNA.) On September 13, as Cramer was finishing her reporting, all five lawsuits were tentatively settled. We don't know all the terms, but we do know that one of the conditions for the settlement was that all the lawsuits be permanently sealed. When that was accomplished, McMahan would write checks — somewhere, we believe, in the range of $7 million to $11 million.

All of that cash, however, couldn't take the court records we were already holding out of our hands. McMahan was simply too late to prevent our story from being published. But his throwing in the towel on the lawsuits and sealing the record would prevent other news organizations from culling records from court files themselves, which may be why more outfits haven't followed the Post's example and done their own stories. (Not that there's a lack of interest. Newsies from Australia to Greece have been asking us to send photographs of Bruce and Linda. Major daily newspapers, glossy magazines, supermarket tabloids, foreign press syndicates, and network television news organizations have all contacted us, asking for a piece of the amazing tale. But I suspect their uptight lawyers are holding them back, since they can't get the lawsuits directly from courthouses on their own.)

Bruce and his money are winning that battle. But he wasn't so fortunate when he tried to rush New Times into court the week our story hit the streets.

Thursday afternoon, the week our story appeared, we received a 37-page fax and a phone call from an attorney telling us that McMahan had convinced a federal judge in Miami to hold an emergency hearing the next morning to consider McMahan's motion for injunctive relief.

McMahan wanted the judge to force us to remove Linda's video deposition from our website, as well as other court documents we posted there, like the 1990 paternity test showing with 99.7 percent certainty that Bruce is Linda's biological father. (But we suspected it was the video that was really giving him indigestion.)

One of our intrepid lawyers, Sandy Bohrer, responded by calling McMahan's people and asking them about their filing. He mentioned that after reading it, he got the impression that they had never heard of something called the First Amendment.

That must have been some phone call. Within minutes, McMahan folded. He withdrew his motion, and the emergency hearing was canceled.

That should be the end of Bruce's legal moves. At this point, only the New York Post has done stories based on Kelly Cramer's reporting, so it's in McMahan's interest not to open another legal can of worms. If he did, he'd have to expose to public view those five sordid court cases that he's paying so much money to seal, and the rest of the news biz would be on them like hounds on a hambone.

Iraq's Missing Dead

In Baghdad, thousands of bodies have been pulled from the Tigris, but the deaths aren't reported. How bad is the violence?

For Macleans.ca, Adnan R. Kahn writes:
Ali is a collector of the dead. That's his job, or at least one of them. He is also a cook at a kebab house in Baghdad and a member of the Mahdi Army, a Shia militia loyal to the militant cleric Muqtada al-Sadr. As a collector, his morbid duty is to sweep up the carnage of a sectarian war spiralling out of control -- one that Iraqi officials and their American overseers are trying desperately to downplay -- and quietly transport it to Iraq's main morgue, located in the heavily fortified Medical City in Baghdad's Bab al-Muatham neighbourhood, where all suspicious deaths are taken.

Every three days, Ali says, he and other al-Sadr militiamen go to the Tigris river to pick up bodies. At a spot on the bank just downstream from the Aima bridge in central Baghdad, a series of eddies gently gather in the dead. "More and more are coming there," Ali says, "from north of Baghdad, from villages like Taji and Balad. Many have their hands tied, most are blindfolded." The method of execution varies, Ali adds, from the basic bullet to the head to more macabre and viciously novel techniques involving power tools, electric cords and other such domestic instruments. "These are all Shia brothers and sisters murdered by Sunnis," says Ali, a Shia militant himself who has carried out his own revenge attacks on Sunnis. When pressed, he admits there "may be" some Sunnis floating down the Tigris as well. "But they were killed in defence of our Shia brothers and sisters," he claims. "They are not innocent victims."

Sectarian hostility aside, there is another aspect to Ali's work that is troubling: the deaths of the people whose bodies he pulls out of the river often go unreported, leading to questions about the real scale of the violence in Iraq. Even the wildly fluctuating official death counts are a stark reminder that Iraqi, and by association U.S. officials, are attempting to minimize a problem getting worse by the day. Earlier this year, the figures released by the government following the Feb. 22 bombing of the Askariya shrine in Samarra, a Shia holy site, which has been cited as the spark that started the current round of killings, were suspiciously lower than numbers provided by morgue officials. But as for the overall picture, a September report published by the United Nations Assistance Mission for Iraq paints a grim picture: civilian deaths reached a record high for July and August with 6,600 civilians killed.

Still, even these figures don't tell the whole story. For that, a visit to Medical City is in order. The Ministry of Health has instituted a strict policy for journalists, requiring them to seek permission before visiting the facility. Those allowed in get only a truly sanitized tour; more often than not reporters are barred from entering. But at the gate, guards who have worked at the facility tell a chilling tale. "Last year, I saw maybe 1,000 bodies a month coming into the morgue," says one man who, fearing for his life, requested his name not be published. "Now we're getting nearly 1,000 a week."

All, he says, are victims of sectarian violence, both Sunni and Shia, but the officials at the morgue inside Medical City will not tell you that. "The officials don't want us talking to the media," says another guard, also requesting anonymity. "I've heard them telling people that most of the deaths are because of terrorists, but I've also seen the bodies myself and I can tell you that most of them were executed by death squads."

While he describes the bodies, a dump truck pulls out of the facility. The guards open the gate, holding back a rush of people from all over central Iraq hoping to get in to look for loved ones. As the truck passes, the smell of decomposing flesh fills the air. "That's just the clothes from bodies pulled from the Tigris over the past few days," says the first guard. "The trucks come and go regularly." The stench is overwhelming. People cover their noses and mouths with cloth. Women wail.

When told about this back at the kebab house, Ali simply shrugs. "You get used to the smell," he says, putting ground beef onto skewers for non-existent customers in a city in which people are too afraid to leave their homes. That job appears to have no potential. But tomorrow, he will be going back to the Tigris to pick up more bodies. That job, at least in Baghdad, has a future.

2,660 Iraqi Civilians Killed In September

The Washington Post reports:
More than 2,660 Iraqi civilians were killed in the capital in September amid a wave of sectarian killings and insurgent attacks, an increase of 400 over the month before, according to figures from the Iraqi Health Ministry.

The increase came despite an intensified U.S.-Iraqi sweep of Baghdad that was launched in mid-August to try to put down the wave of violence that has swept over the capital. The violence consists of a deadly combination of bombings and shootings by Sunni insurgents, and slayings by Shiite and Sunni death squads.

The September numbers come as a controversial new study contends that nearly 655,000 Iraqis have died in the three-year-old conflict in Iraq _ more than 10 times higher than other independent estimates of the toll.

President Bush dismissed as "just not credible" the study's estimate study that contends nearly 655,000 Iraqis have died because of the war.

Bush, who in the past has suggested 30,000 civilian deaths in Iraq, would not give a figure for overall fatalities. "A lot of innocent people have lost their life," he said at a news conference in Washington.

The study, which is to be published Thursday on the Web site of The Lancet, a medical journal, was based on a survey of households in Iraq, not a body count, and quickly raised skepticism among some Iraq experts.

Pentagon spokesman Bryan Whitman said it was difficult "with any certainty" to estimate the number of Iraqi civilians who have died, and said the department does everything possible to prevent civilian casualties.

"We take great precautions in our military operations," he said. "That's in stark contrast to what the enemy in Iraq is doing. They take no such precautions. In fact, they deliberately target innocent civilians in their attacks."

An accurate count of total Iraqi deaths since the war's start has been difficult to obtain. According to an Associated Press tally, at least 13,414 Iraqis have been killed in war-related violence through Tuesday since the new government took office on April 28, 2005. Of those, 9,300 were civilians.

The AP tally is compiled from hospital, police and military officials cited in news stories, as well as accounts from reporters and photographers at the scenes. The actual number is likely higher as many killings go unreported or uncounted.

A private group called Iraqi Body Count says it has recorded about 44,000 to 49,000 civilian Iraqi deaths. But it notes that those totals are based on media reports, which it says probably overlook "many if not most civilian casualties."

The figures for the number of civilian deaths in September in Baghdad came in an official monthly report from the Health Ministry to the Cabinet on the number of Baghdad victims of violent deaths, two senior ministry officials told The Associated Press.

The two officials spoke on condition of anonymity because the government has issued orders that the death figures not be released. Civilian casualty numbers are always sensitive, and several other officials in the Health and Interior ministries contacted by the AP refused to give statistics.

The report said 2,667 civilians had died violent deaths in September _ an average of 89 a day. Those deaths include bodies found dumped around Baghdad and the victims of explosions, shootings and other attacks, the two officials said.

By comparison, 2,222 people died violently in August in Baghdad, according to a U.N. report published in September, which is also based on official statistics from the Health Ministry.

The two ministry officials said the U.N. number was accurate for the August deaths.

The monthly figures include two categories. One is the number of bodies found in Baghdad, provided from the city morgue, where the bodies are taken to determine the cause of death.

In September, the morgue reported 1,471 bodies of people who died from violence.

Shiite and Sunni death squads are known to kidnap members of the opposing sect, then dump bodies of their victims, often bound and tortured. So a large proportion of the 1,471 bodies are likely from sectarian killings _ though they also would include victims of criminal kidnappings and murders.

The other category included in the monthly figure encompasses the victims of explosions, shootings or other attacks, reported by hospitals. They numbered 1,196 in September, according to the report, the two Health Ministry officials said.

In August, 1,536 bodies were brought to the morgue, according to the U.N. report.

The past summer has seen a startling increase in bloodshed, centered in the capital, after the wave of sectarian violence was sparked by the February bombing of a Shiite shrine in the city of Samarra, north of Baghdad.

The deadliest month was July, when 3,590 people were killed across the country _ 2,884 of them in Baghdad, according to the U.N. The number killed countrywide fell in August to 3,009, the U.N. said.

The Health Ministry officials who spoke to the AP did not have September figures for the entire country, only for Baghdad.

Old Death In The New Iraq

Cervantes at Stayin' Alive weighs in on the Lancet study:

Okay, the Lancet doesn't come out until tomorrow but you can already get the manuscript of the Johns Hopkins/Al Mustansiriya/MIT study on excess deaths in Iraq here. Since we're already hearing that it's just a political stunt, not reliable, etc., I figured I ought to offer my take on it.

As readers of Today in Iraq know, there are daily death tolls reported by the Baghdad morgue, the police, and stringers around the country who feed information to the major news services who have offices in Iraq -- AP, AFP, Reuters, KUNA (the Kuwait news agency) and Xinhua (the Chinese agency) provide the bulk of the available information. Many people assume that the reports they read in the newspaper, usually from AP, or the daily Reuters "fact box" report that many bloggers (including Atrios and Juan Cole) often repost, are more or less complete descriptions of the day's violence. In fact, they don't even come close.

By combining information from all of the available sources, we always come up with at least two or three times as many violent incidents as you will find in any one source. Even so, it's pretty obvious that most deaths by violence in Iraq never get noted by the police, the morgue, or the news services. Out of deference to their masters, the Iraqi authorities generally don't try to count people killed by the occupation forces. Much of the country is off limits to journalists. Many people who are shot dead never end up in the morgue and there certainly isn't any reason for Iraqis to make police reports. (Police or other security forces, or people dressed like them, are responsible for most of the murders in the first place.) Muslims bury their dead quickly and relatively unceremoniously, and, while the health ministry issues death certificates, it has no system for aggregating and reporting vital records data.

So, the researchers set out to estimate deaths by means of a household survey using area probability sampling methods. This is a method used all the time in health surveys. It's a method I have used myself, in fact. To begin, you just need census data -- it actually doesn't even have to be highly accurate as long as any errors are essentially random, or unrelated to your study questions. Then, you pick geographic areas based on probability proportionate to the population they contain. This is usually done in stages. In the Iraq study, they first determined the number of clusters they would select in each province based on population size (Baghdad, with its population of over 6 million, got 12; Muthanna, with a population of 570,000, happened to get none.) Then, towns, blocks, and starting households were selected at random. For each household selected, the 39 nearest houses were also included. This survey had a total of 47 clusters, including 12,801 persons.

The researchers interiewed adult household members between May and June, 2006, to learn about births, deaths, and migration since January 1, 2002. They also asked people to report if an entire neighboring household had been wiped out, to account for households with no-one left to speak for them. They report that for 92% of reported deaths, the respondents were able to produce a death certificate. A substantial omission in the report, I must say, is the failure to state the response rate. The investigators also refer to procedures for substituting areas which were too unsafe to visit. They do not say how often this happened, but if anything, it would tend to bias the results downward.

To arrive at an estimate of total deaths for the country, they simply multiply the deaths in the study population by the appopriate weights for the number of people each cluster represents (i.e., the inverse of the probability that a person living in that province would have been selected). The clustering does not directly affect the estimates, but it does affect the so-called confidence interval. Since people living in a specific area are at greater or lesser risk of violent death than average, the statistical power of the study is less than it would be for a single stage probability sample of 12,801 persons, because of the possibility that the selection of clusters introduced sampling error. Although the manuscript does not discuss the specific calculations that were done to adjust for this, I am willing to give investigators from these institutions the benefit of the doubt that they did it correctly.

It is conventional to report 95% confidence intervals. The researchers find that there is a 95% probability, assuming no systematic biases in their data, that there have been between 426,369 and 793,663 excess deaths from violence among Iraqis since the invasion -- i.e., deaths that would not have occurred had the death rate continued as before. (There were very few violent deaths in Iraq prior to the invasion. The famous mass graves date from the era of the Iran-Iraq war, and suppression of Kurdish and Shiite rebellions associated with that era.) The investigators also estimate that there have been about an additional 54,000 deaths from non-violent causes, mostly in 2005-2006, as Iraq's health care and public health infrastructure severely deteriorated.

The steady increase in violent death rates is quite appalling, from 3.2/1,000/year in March 2003-April 2004; to 12/1,000/year from June 2005-June 2006. Not surprisingly, the deaths are concentrated in Baghdad and the predominantly Sunni Arab areas of the country. The three provinces of autonomous Kurdistan have been peaceful. 31% of violent deaths were caused by coalition forces, 24% by other actors, and in 45% of cases the perpetrators were unknown to the respondents. Even if none of these were caused by coalition forces, it results that U.S. troops have killed about 200,000 Iraqis, with perhaps a modest contribution from the British.

Are these results reliable? They are in fact the most reliable information we have about this subject. Particularly powerful confirmation comes from the very close match in this survey between deaths reported to have occurred in 2003-2004; and the results from a similar study conducted by the team in 2004. That of course had an entirely different sample of households, but used the same methods. People often misunderstand the concept of the confidence interval. It is far more likely that the true number of violent deaths is close to 600,000, than that it is close to 427,000. People also do not understand how a sample consisting of such a small percentage of the population can give us confidence in saying something about the entire population. But that results from the laws of probability, which assure that state lotteries and casinos will always win.

Was the release of this report politically motivated? Possibly the authors made a special effort to get it out before the election, but that has no relation to its truth.

Finally, as I have said many times, Iraq Body Count should go out of business. They are doing positive harm to the reality based community by giving the perpetrators of this world historical crime cover for saying that the death toll is only 10% of what it really is. That is not helping the Iraqi people.

UPDATE: Thanks to a tip from Whisker, here's an article that shows that innumerable violent deaths in Iraq go unreported.

Study Claims Iraq's 'Excess' Death Toll Has Reached 655,000

The Washington Post reports:
A team of American and Iraqi epidemiologists estimates that 655,000 more people have died in Iraq since coalition forces arrived in March 2003 than would have died if the invasion had not occurred.

The estimate, produced by interviewing residents during a random sampling of households throughout the country, is far higher than ones produced by other groups, including Iraq's government.

It is more than 20 times the estimate of 30,000 civilian deaths that President Bush gave in a speech in December. It is more than 10 times the estimate of roughly 50,000 civilian deaths made by the British-based Iraq Body Count research group.

The surveyors said they found a steady increase in mortality since the invasion, with a steeper rise in the last year that appears to reflect a worsening of violence as reported by the U.S. military, the news media and civilian groups. In the year ending in June, the team calculated Iraq's mortality rate to be roughly four times what it was the year before the war.

Of the total 655,000 estimated "excess deaths," 601,000 resulted from violence and the rest from disease and other causes, according to the study. This is about 500 unexpected violent deaths per day throughout the country.

The survey was done by Iraqi physicians and overseen by epidemiologists at Johns Hopkins University's Bloomberg School of Public Health. The findings are being published online today by the British medical journal the Lancet.

The same group in 2004 published an estimate of roughly 100,000 deaths in the first 18 months after the invasion. That figure was much higher than expected, and was controversial. The new study estimates that about 500,000 more Iraqis, both civilian and military, have died since then -- a finding likely to be equally controversial.

Both this and the earlier study are the only ones to estimate mortality in Iraq using scientific methods. The technique, called "cluster sampling," is used to estimate mortality in famines and after natural disasters.

While acknowledging that the estimate is large, the researchers believe it is sound for numerous reasons. The recent survey got the same estimate for immediate post-invasion deaths as the early survey, which gives the researchers confidence in the methods. The great majority of deaths were also substantiated by death certificates.

"We're very confident with the results," said Gilbert Burnham, a Johns Hopkins physician and epidemiologist.

A Defense Department spokesman did not comment directly on the estimate.

"The Department of Defense always regrets the loss of any innocent life in Iraq or anywhere else," said Lt. Col. Mark Ballesteros. "The coalition takes enormous precautions to prevent civilian deaths and injuries."

He added that "it would be difficult for the U.S. to precisely determine the number of civilian deaths in Iraq as a result of insurgent activity. The Iraqi Ministry of Health would be in a better position, with all of its records, to provide more accurate information on deaths in Iraq."

Ronald Waldman, an epidemiologist at Columbia University who worked at the Centers for Disease Control and Prevention for many years, called the survey method "tried and true," and added that "this is the best estimate of mortality we have."

This viewed was echoed by Sarah Leah Whitson, an official of Human Rights Watch in New York, who said, "We have no reason to question the findings or the accuracy" of the survey.

"I expect that people will be surprised by these figures," she said. "I think it is very important that, rather than questioning them, people realize there is very, very little reliable data coming out of Iraq."

The survey was conducted between May 20 and July 10 by eight Iraqi physicians organized through Mustansiriya University in Baghdad. They visited 1,849 randomly selected households that had an average of seven members each. One person in each household was asked about deaths in the 14 months before the invasion and in the period after.

The interviewers asked for death certificates 87 percent of the time; when they did, more than 90 percent of households produced certificates.

According to the survey results, Iraq's mortality rate in the year before the invasion was 5.5 deaths per 1,000 people; in the post-invasion period it was 13.3 deaths per 1,000 people per year. The difference between these rates was used to calculate "excess deaths."

Of the 629 deaths reported, 87 percent occurred after the invasion. A little more than 75 percent of the dead were men, with a greater male preponderance after the invasion. For violent post-invasion deaths, the male-to-female ratio was 10-to-1, with most victims between 15 and 44 years old.

Gunshot wounds caused 56 percent of violent deaths, with car bombs and other explosions causing 14 percent, according to the survey results. Of the violent deaths that occurred after the invasion, 31 percent were caused by coalition forces or airstrikes, the respondents said.

Burnham said that the estimate of Iraq's pre-invasion death rate -- 5.5 deaths per 1,000 people -- found in both of the Hopkins surveys was roughly the same estimate used by the CIA and the U.S. Census Bureau. He said he believes that attests to the accuracy of his team's results.

He thinks further evidence of the survey's robustness is that the steepness of the upward trend it found in excess deaths in the last two years is roughly the same tendency found by other groups -- even though the actual numbers differ greatly.

An independent group of researchers and biostatisticians based in England produces the Iraq Body Count. It estimates that there have been 44,000 to 49,000 civilian deaths since the invasion. An Iraqi nongovernmental organization estimated 128,000 deaths between the invasion and July 2005.

The survey cost about $50,000 and was paid for by Massachusetts Institute of Technology's Center for International Studies.