Calculated Risks: How to know when numbers deceive you by Gerd Gigerenzer, Simon & Schuster, $25, ISBN 0743205561
WE ALL have to learn to deal with statistics, because there鈥檚 no such thing as absolute certainty. This is the message of Gerd Gigerenzer鈥檚 highly readable Calculated Risks. Cancer and HIV screening programmes throw up false positives, with potentially devastating consequences for the people who are misdiagnosed. Genetic fingerprinting, increasingly used as evidence in the courts, isn鈥檛 as foolproof as juries are sometimes led to think.
Most people simply don鈥檛 understand statistics or how to apply them appropriately. Even doctors and lawyers struggle to cope with the data relevant to their professions. To stem this tide of innumeracy, Gigerenzer prescribes a four-step approach through which anyone can become confident in handling statistics. And his method works. First, give up the comforting illusion of certainty, and then we need to discover the true magnitude of risks. Then we must learn to communicate the numbers in a clear and comprehensible fashion, and finally to combat the clouded thinking that so often leads us to draw false conclusions from the data.
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This is an important book, full of relevant examples and worrying case histories. By the end of it, the reader has been presented with a powerful set of tools for understanding statistics. Doctors, lawyers and anyone who wants to take responsibility for their own medical choices should read it.