epidemic thinking


Let me tell you the basics of risk communication, and then I want to apply them, a little bit, to bird flu. The fundamental principle of risk communication can be summarized in a number, [which] is the correlation between how much harm a risk does and how upset people get about it. If you look at a long list of risks, and you rank them in order of how upset people get [about them], then you rank them again in order of how much harm they do, then you correlate the two, you get a glorious 0.2. Those of you who remember your statistics know you can square a correlation coefficient to get the percentage of variance accounted for: If you square 0.2, you get 0.04, or 4% of the variance. That is, the risks that kill people and the risks that upset people are completely different. If you know that a risk kills people, you have no idea whether it upsets them or not. If you know it upsets them, you have no idea whether it kills them or not.

more from UPMC here (via Marginal Revolution).