About a year ago, a John Hopkins University study in the British medical journal The Lancet estimated the number of civilian casualties in Iraq. It came up with a number—100,000 dead—that was higher than any other estimate, and was mostly ignored. This week, Producer Alex Blumberg tells the remarkable story of what it took to find that number, why we should find it credible and why almost no one believed it. (The original Lancet study is online; free registration is required). (38 minutes)