Efect Measure

I'm guessing most everyone interested in swine flu already reads Effect Measure (as well you should; it was an invaluable resource in my reporting for my Slate piece on the mystery of the virulence of the outbreak in Mexico). But in case you haven't or are not, today's primer there on case fatality rates, virulence, and mortality would make an excellent start. One of the things we'd like to know about the swine flu virus is its Case Fatality Ratio (CFR, commonly called a case fatality rate, although it isn't technically a rate but a proportion). But what is a CFR? And how is it different…