Authors of a study that provided sharply higher figures for the number of Iraqis killed since the beginning of the war in Iraq in 2003, have strongly defended the methods they used. VOA's Dan Robinson reports, the authors appeared for the first time on Capitol Hill, to give their personal views in support of the findings.

Residents clean blood from the street following an explosion in Hillah, about 95 kilometers (60 miles) south of Baghdad, Iraq, Sunday, Nov. 19, 2006

Based on surveys in Iraq, the report, published in the British medical journal The Lancet, estimated that 655,000 more people have died since U.S. and coalition forces invaded Iraq then would have been the case under pre-war mortality rates. Of the total, 601,000 of the deaths were attributed to violence.

Co-author Gilbert Burnham, of the Center for Disaster and Refugee Response of Johns Hopkins University School of Public Health, stands as firmly behind the results as when they sparked so much controversy in October:

"In this survey we collected more than enough data to measure a doubling of the death rates that occurred before the time of the invasion," said Gilbert Burnham.

While Burnham remains confident of the accuracy of the 655,000 casualty figure, he says the lowest number for which the report attaches a high degree of confidence is about 393,000.

He adds that, while much of the U.S. and international media reporting on violence has come from Baghdad, the problem is more widespread.

"The violence was spread right across the country," he said. "The vast majority of these deaths were in males although there was an interesting look at deaths among children under age 15, and that was increased perhaps out of proportion to what I might have expected."

The Johns Hopkins study, and a similar one by the authors in 2004 estimating the death toll at about 100,000, were criticized by the U.S. and British governments.

Critics took issue with the survey methods used, saying the report was based on extrapolation rather than using actual body counts, and asserting that the 655,000 figure was itself highly questionable.

But the co-authors also received support from many survey experts, and say their technique called "cluster surveys" is reliable and used by the U.S. and foreign governments and the United Nations, especially when doubts exist about information from official sources.

Les Roberts, report co-author and a lecturer at Johns Hopkins and Columbia University, says the report raises troubling questions.

"Would Congress have approved this [military action] had they known in advance," asked Les Roberts. "Can the press pretend they have done even a credible job of reporting in Iraq if they have consistently downplayed the number of deaths by a factor of ten? Can we in academia and in those think-tanks around Washington, pretend that we add value to discourse in society if something almost identical in magnitude to the Rwandan genocide could more or less go unnoticed by our society?"

Juan Cole, Professor of Middle East and South Asian History at the University of Michigan says the findings have many long-term effects for Iraqi society.

"The insecurity makes development impossible," he said. "It makes it impossible for say the women to take up the slack, it makes it impossible for new economic ventures to be established."

The co-authors of the reports say future studies should focus on the implications of the violence in Iraq, although doing so would require a certain degree of security in the country.

Les Roberts suggests new evidence might provide a more accurate picture of casualties, but should be accompanied by a sincere acknowledgement by the U.S. and others of the toll in Iraq.

"The main thing we are missing in our society at this moment in time is the tone of contrition that should go along with having inadvertently, perhaps no one could have envisioned it, I don't care, but done great harm to another people," he said. "So, the most important thing should be that a reasonable estimate be generated, believed, quoted and become the common dialogue of the U.S. government."

Responding to the report in October, President Bush questioned its methodology, describing it as "not credible." In 2005, he said he believed that 30,000 Iraqis had died since 2003 from violence and the initial military invasion.

The Pentagon said it "regretted the loss of any innocent life in Iraq or anywhere else" adding 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."