Recent Articles on L2
First, a tour de force (pdf) from Michael Spagat: "Ethical and Data-Integrity Problems in the Second Lancet Survey of Mortality in Iraq." This is the paper that I wanted to write last summer, but was not smart or organized enough to do. Michael will be presenting this paper at JSM in August.
Second, "Estimating mortality in civil conflicts: lessons from Iraq" by Debarati Guha-Sapir and Olivier Degomme (pdf) is critical of L2. The authors identify several "errors and methodological weaknesses" of L2 and write:
Our re-estimation of total war-related death toll for Iraq from the invasion until June 2006 is therefore around 125,000.
This is less than 1/4 of the comparable L2 estimate of 601,000.
Third, a 2006 working paper (pdf) by Mark J. van der Laan. He argues that the reported confidence interval for L2 is significantly too narrow.
Fourth, the IFHS study. They estimate about 151,000 violent deaths over the same period as L2. Again, this is around 1/4 the L2 estimate. M. Ali, one of the authors, will be presenting on my panel at JSM.
Good stuff all.
Where does that leave my estimate of excess war deaths? Time to update with the information in these studies. Recall that I wrote two years ago:
If I had to bet, I would provide much wider confidence intervals than either the Lancet authors or most of their critics. Burnham et al. (2006) estimate 650,000 "excess deaths" since the start of the war with a 95% confidence interval of 400,000 to 950,000. My own estimate would center around 300,000 and range from 0 to 1.2 million.
Then, last month, I updated to:
So, my new estimate is 150,000 (at first glance, this new paper seems much better than L1 or L2) with a confidence interval of 0 to 500,000.
This still seems OK, but I think that the upper bound can start to come down. When experience scholars like the folks at IFHS and CRED come up with independent (?) estimates with upper confidence intervals well below 500,000, then I can be fairly sure that this is too conservative. So, now I go with 125,000 (shifting a little lower than IFHS because I am impressed with the view that the IFHS estimate does too much adjustment for dangerous clusters that were not sampled) and a range of 0 to 300,000.
All of this, of course, depends on the assumption that the mortality rate in Iraq, in the absence of war, would have been similar to that of Iraq in 2002 to 2003. In other words, I assume that Sadam would not have attacked Iran, gassed the Kurds, taken revenge on the Shiites and so on. Whatever probability you assign to those events, you should decrease your excess death estimates accordingly.