Could 650,000 Iraqis really have died because of the invasion?

The numbers are horrible no matter what, but 650 thousand does seem too many:

The statistics made headlines all over the world when they were published in The Lancet in October last year. More than 650,000 Iraqis – one in 40 of the population – had died as a result of the American-led invasion in 2003. The vast majority of these “excess” deaths (deaths over and above what would have been expected in the absence of the occupation) were violent. The victims, both civilians and combatants, had fallen prey to airstrikes, car bombs and gunfire.
Body counts in conflict zones are assumed to be ballpark – hospitals, record offices and mortuaries rarely operate smoothly in war – but this was ten times any other estimate. Iraq Body Count, an antiwar web-based charity that monitors news sources, put the civilian death toll for the same period at just under 50,000, broadly similar to that estimated by the United Nations Development Agency.

The implication of the Lancet study, which involved Iraqi doctors knocking on doors and asking residents about recent deaths in the household, was that Iraqis were being killed on an horrific scale. The controversy has deepened rather than evaporated. Several academics have tried to find out how the Lancet study was conducted; none regards their queries as having been addressed satisfactorily. Researchers contacted by The Times talk of unreturned e-mails or phone calls, or of being sent information that raises fresh doubts. Read More.