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Book Review - ‘The Drunkard’s Walk,’ by Leonard Mlodinow - Review - NYTimes.com

When statistics are used in a court of law the effect can be just as misleading. Mlodinow recalls the O. J. Simpson trial, in which the prosecution depicted the defendant as an inveterate wife abuser. One of Simpson’s lawyers, Alan Dershowitz, countered with statistics: in the United States, four million women are battered every year by their male partners, yet only one in 2,500 is ultimately murdered by her partner.

The jury may have found that persuasive, but it’s a spurious argument. Nicole Brown Simpson was already dead. The relevant question was what percentage of all battered women who are murdered are killed by their abusers. The answer, Mlodinow notes, didn’t come up in the trial. It was 90 percent.

Lawyers, it seems, are no better than doctors at this kind of math. But juries are even worse.

Excellent example. The first statistic, prima facie, has some relevance. The scales fall from our eyes only when the question is formulated in the correct way. Salutary.Technorati Tags: statistics, law, dershowitz, mlodinow