UNITED NATIONS - How many Iraqi civilians have lost their lives as a result of gunshots and bombings since the U.S. military invaded that oil-rich Arab nation nearly five years ago?

Credible estimates for the period March 2003 until June 2006 have ranged from a high of 600,000 to about 47,000. The first figure was reported by researchers from Johns Hopkins in The Lancet, a venerable British medical journal, back in October 2006. The second one was projected by the independent organisation Iraq Body Count (IBC).

This week, the World Health Organisation (WHO) and the Iraqi Health Ministry released a joint survey suggesting that no less than 151,000 Iraqis died violently during that time frame.

The U.S. government does not tally violence-related Iraqi deaths, not does it intend to. However, a little over a year ago, President George W. Bush casually suggested that the numbers could be around 30,000.

So which figures are reliable? It is difficult to say for certain, although there is no doubt that the U.S. military invasion and occupation is largely responsible for the huge loss of human life in Iraq.

According to WHO and Iraqi researchers, since the invasion, violence has been the leading cause of death for Iraqi men between the ages of 15 and 59. About half of these deaths have taken place in the capital city of Baghdad, according to the survey, which was largely based on interviews with more than 9,000 households in nearly 1,000 villages and neighbourhoods across the country.

The study did not attempt to determine whether the deaths were caused by Coalition Forces, militia groups or others. It also omits the period of the most intense sectarian violence from mid-2006 to mid-2007.

The findings and methodology of the study, entitled "Violence-Related Mortality in Iraq from 2002 to 2006", were published in the Jan. 8 online edition of the New England Journal of Medicine (NEJM).

The survey indicates that a year after the U.S. invasion, about 128 Iraqis were dying every day. That average remained more or less the same until June 2006 when the study was completed.

Though successful in their efforts to complete the survey, researchers acknowledged that at times they faced great difficulties in obtaining information due to ongoing violence and displacement.

"Assessment of the death toll in conflict situations is extremely difficult and household survey results have to be interpreted with caution," said Mohamed Ali, a WHO statistician and the study's co-author.

As a result, the study's statistical estimates suggest that war-related deaths range anywhere from 104,000 to 223,000.

If there is no comprehensive death registration and hospital reporting available, said Ali, then "household surveys are the best we can do."

The new estimate is three times higher than the death toll compiled through careful screening of media reports and other data by Iraq Body Count and about four times lower than a smaller-scale household survey conducted by The Lancet.

The Lancet study was based on previously accepted methods for calculating deaths rates to estimate the numbers of "excess" Iraqi deaths after the 2003 invasion at 426,369 to 793,663. It said the most likely figure was in the middle range: 654,965.

Almost 92 percent of those dead, according to the study, were killed by bullets, bombs or U.S. air strikes, a stunning toll that was more than 10 times the number of deaths estimated by any organisation at the time.

The figures projected in the June 2006 report sent shockwaves across the United States and the world. It was widely covered by the mainstream press, amid calls for the Bush administration to reconsider its Iraq policy.

Some critics have expressed discomfort with The Lancet's methodology, arguing that the statistical analysis is deeply flawed and reeks of political bias against the United States.

Last week, in a lengthy article published in the National Journal, writers Neil Munro and Carl Cannon concluded that the study not only "lacks transparency in the data", but also disengagement from "ideological leanings".

Les Roberts, co-author of The Lancet study, said in a statement Friday that, "The NEJM article found a doubling of mortality after the invasion, we found a 2.4-fold increase. Thus, we roughly agree on the number of excess deaths. The big difference is that we found almost all the increase from violence, they found one-third of the increase from violence."

"This new estimate is almost four times the 'widely accepted' [Iraq Body Count] number from June of 2006, our estimate was 12 times higher. Both studies suggest things are far worse than our leaders have reported," he said.

Roberts also said the NEJM data could reflect an under-reporting of violent deaths. "It is likely that people would be unwilling to admit violent deaths to the study workers who were government employees," he noted.

"Finally, their data suggests one-sixth of deaths over the occupation through June 2006 were from violence. Our data suggests a majority of deaths were from violence. The morgue and graveyard data I have seen is more in keeping with our results."

For their part, the WHO-Iraq study's authors openly acknowledge that they were not able to reach out to all the families they had planned to conduct interviews with, in part because many people had fled their homes.

"[All] these factors were taken into account in the analysis as they may affect the accuracy of the survey work," said Salih Mahdi Motlab Al-Hasanawi, Iraq's minister of health. "Nonetheless, the survey results indicate a massive death toll since the beginning of the conflict."

WHO officials said the study was originally meant to help Iraqi government plan its health policies and services. In addition to deaths, the survey also focused on other health-related issues, such as pregnancy, sexually transmitted infections, and domestic violence.

According to the study, 57 percent of the women surveyed in Iraq appeared to be fully aware of HIV/AIDS and its consequences. That compares with 84 percent of women in Turkey and Egypt, 91 percent in Morocco and 97 percent in Jordan.

© 2008 Inter Press Service