Monday, January 09, 2006
Cockburn describes the random sampling methodoloy of the now almost forgotten Lancet study in light of the more commonly cited, and predictably, lesser casualty figures provided by iraqbodycount.org:
Cockburn also makes short shrift of the claim that the sample was distorted by data developed from Fallujah:
Epidemiologists use it to chart the impact of epidemics. In 2000 an epidemiological team led by Les Roberts of Johns Hopkins School of Public Health used random sampling to calculate the death toll from combat and consequent disease and starvation in the ongoing Congolese civil war at 1.7 million. This figure prompted shocked headlines and immediate action by the UN Security Council. No one questioned the methodology.
In September 2004, Roberts led a similar team that researched death rates, using the same techniques, in Iraq before and after the 2003 invasion. Making "conservative assumptions" they concluded that "about 100,000 excess deaths" (in fact 98,000) among men, women, and children had occurred in just under eighteen months. Violent deaths alone had soared twentyfold. But, as in most wars, the bulk of the carnage was due to the indirect effects of the invasion, notably the breakdown of the Iraqi health system. Thus, though many commentators contrasted the iraqbodycount and Johns Hopkins figures, they are not comparable. The bodycounters were simply recording, or at least attempting to record, deaths from combat violence, while the medical specialists were attempting something far more complete, an accounting of the full death toll wrought by the devastation of the US invasion and occupation.
Significantly, Cockburn consults a statistician, Pierre Sprey, who, after a detailed explication of his technique, and his interpretation of the data from the Lancet study, comes to this disquieting conclusion:
Some questioned whether the sample was distorted by unrepresentative hot spots such as Fallujah. In fact, the amazingly dedicated and courageous Iraqi doctors who actually gathered the data visited 33 "clusters" selected on an entirely random basis across the length and breadth of Iraq. In each of these clusters the teams conducted interviews in 30 households, again selected by rigorously random means. As it happened, Fallujah was one of the clusters thrown up by this process. Strictly speaking, the team should have included the data from that embattled city in their final result - random is random after all -- which would have given an overall post-invasion excess death figure of no less than 268,000. Nevertheless, erring on the side of caution, they eliminated Fallujah from their sample.
183,000 to 511,000? It strikes the reader as beyond comprehension, until one recalls Joe's post about the expanded air war, a subject that I hope to address as well in the coming days.
Of course the survey on which all these figures are based was conducted fifteen months ago. Assuming the rate of death has proceeded at the same pace since the study was carried out, Sprey calculates that deaths inflicted to date as a direct result of the Anglo-American invasion and occupation of Iraq could be, at best estimate, 183,000, with an upper 95 per cent confidence boundary of 511,000.