The mathematical guts of the paper is that under certain assumptions, the addition of the very violent cluster in Fallujah can add so much uncertainty to the estimate of the post-invasion death rate that it stretches the bottom end of the 95% confidence interval for the risk rate below 1. From this, David Kane concludes that the paper was wrong to reject the hypothesis that the Iraq War had not made things worse.
Let’s back up and look at that again. Under David Kane’s assumptions, the discovery of the Fallujah cluster was a reason to believe that things might have gone better in Iraq. This clearly means that these were the wrong assumptions.
The statistical problem here is basically that people can’t come back from the dead. The Fallujah datapoint increases the uncertainty of the estimate, but it doesn’t increase it in both directions, because there is no way that you could find an “anti-Fallujah” (a datapoint which brought the overall average down by as much as real Fallujah brought it up), because such a place would need to have a negative death rate.
And looking at the charts in David’s paper, it’s clear to see that the reason why the left edge of his estimate of the risk ratio has been dragged below 1 is that a substantial part of the distribution of his Bayesian estimate of the post-war death rate is below zero (and an even more substantial part is in regions of positive but wildly improbably death rates like one or two per 100K). That’s all there is to it, CT readers; the majority of the rest of the Deltoid thread consists of three or four people trying to explain that the Roberts et al. paper doesn’t make the same mistake.
Gavin M comments:
Look for new claims by the usual right-wing foundation hacks that the Lancet study has been ‘definitively debunked,’ and chalk up another petty, rigged ‘victory’ to the distributed intelligence of the WingNet.
They obviously did not do a proper peer review on the paper before they accepted it and that may well be because they were so out of their field that they did not know how to do a proper review of a survey research paper. They should stick to medicine.
It may be noted that the authors of the paper refuse to release their raw data — a most unusual thing for scientists to do. It suggests that the “research” was a fraud from beginning to end — rather like the Mann “hockeystick” finding in climate science — a finding that the IPCC no longer mentions!
Something Michelle seems to have overlooked, however, is that there seems to have been an attempt by Lancet to redact what they originally published. The paper Michelle cites is a version that says only 100,000 Iraqis died. Whereas the original paper said that 654,965 Iraqis died. Is this an admission? Does even Lancet now concede that they goofed? The plot thickens!
Let’s see, epidemiology is part of medicine, the hockeystick is not a fraud, the IPCC still mentions it, and there have been two different surveys on Iraqi deaths covering different time frames published in the Lancet. So much wrong in such a small space…