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.