By Kate Kelland
LONDON (Reuters) - More than 92,600 civilians were killed in armed violence in Iraq from 2003 to 2008, and U.S.-led coalition forces showed higher rates of indiscriminate killing of women and children than insurgents, a study has found.
British and Swiss researchers, using data from the human rights group Iraq Body Count (IBC), analyzed civilian deaths in Iraq from March 2003 to March 2008 and found that most killings were committed by unknown perpetrators, often from extrajudicial executions, suicide bombs, vehicle bombs, and mortars.
But according to a "dirty war index" devised by the researchers to measure the proportion of women and children among civilians killed by certain kinds of weapons, coalition forces also did poorly.
The study found that the most indiscriminate effects on women and children in Iraq were from unknown perpetrators firing mortars - with a dirty war index (DWI) rating of 79 - and using non-suicide vehicle bombs, with a DWI of 54, and from coalition air attacks, with a DWI of 69.
For all types of weapons combined, and for small arms fire, coalition forces had a higher dirty war index rating than anti-coalition forces, the researchers said.
Madelyn Hsiao-Rei Hicks of the Institute of Psychiatry at King's College London, who led the study, stressed that this did not mean coalition forces had killed more women and children, but that there was a high proportion of women and children among the civilians they killed.
"Some weapons are inherently more indiscriminate, such as large explosive weapons - whether they are suicide bombs or aerial bombs," she said in a telephone interview.
The study was published on Tuesday in the open-access journal Public Library of Science (PLoS) Medicine.
Hicks said the findings suggested that some of the types of weapons used by American-led forces during the invasion of Iraq in 2003, and subsequently, were not very precise.
"If you use heavy aerial bombing in a populated area, it is likely to have a more indiscriminate effect on women and children," she said.
Another possible reason behind the high dirty war index rating for U.S.-led forces, she said, was that their opponents are not part of an established force, do not wear uniforms and so cannot easily be distinguished from ordinary civilians.
"The anti-coalition forces tend to draw coalition fire toward them into civilian areas," she said. "Because this is an irregular war, that is going to increase civilian casualties."
Iraq Body Count (IBC) is a non-governmental project that collates media reports of deaths of individual Iraqi civilians and cross-checks them against data from hospitals, morgues, other non-governmental organizations and official figures.
Its latest report in December found that the number of Iraqi civilians killed in violence fell to its lowest level in 2010 since the 2003 U.S.-led invasion.
PLoS Medicine 2011.