An academic whose estimates of civilian deaths during the Iraq war sparked controversy has been criticised for not fully co-operating with an inquiry.
Gilbert Burnham said in the Lancet medical journal in 2006 that 650,000 civilians had died since 2003 - a figure far higher than other estimates.
A polling association in the US said Dr Burnham had refused to supply "basic facts" for its inquiry into his work.
It did not comment on the accuracy of his conclusion.
The American Association for Public Opinion Research (AAPOR)began investigating Dr Burnham's work in March 2008 after a complaint by one of its members.
His research was based on a survey of Iraqi households and concluded that by July 2006 about 655,000 Iraqi civilians had died as a result of the US-led invasion.
The Iraqi government does not keep precise records of civilians killed and neither do US forces, but in 2006 the Iraqi health ministry estimated that between 100,000 to 150,000 civilians had died.
things that make you go hmmmmm
