You could call this a non-fiction novel. You could, that is, if that genre name hadn’t been pre-empted by Truman Capote back in the ’60s. Or you could call it historical fiction, if that genre name hadn’t had a long history of placing fictional events and characters in real historical contexts.
Whatever the label, The Mathematical Murder of Innocence is a fascinating account of a slightly fictionalized trial, in which math is used in order to acquit an innocent defendant. It should have been a case on Numb3rs. As I suggest above, this book is based on a couple of real cases, with two different defendants but the same “expert” witness in both. In each case a woman is convicted of murdering two babies because statistics “showed” that the chances that the mother was innocent (that it was merely SIDS) were so low as to be unbelievable.
Except that the math was wrong.
And you can’t expect a random American jury to understand math and statistics, can you? (Actually, in this case it’s a random British jury, but the point is the same.) It’s very easy to show that even a group of Advanced Placement Statistics students are terrible at estimating risks.
Fortunately, author Michael Carter writes in such a way that the reader doesn’t need a deep understanding of probability, Simpson’s Paradox, and Bayes’ Theorem (although it couldn’t hurt). Crib death — apparently called cot death in Britain — is of course a real phenomenon, and I’m confident that the statistics cited in the narrative are all real. At the heart of the story is the claim that “one cot death is a tragedy, two are a crime,” despite what Mark Twain (may have) said: “There are lies, damn lies, and statistics.”
The story is convincingly based on the work of real-life statistician Nassim Nicholas Taleb (pictured below), famous for his analysis of black swan events and cited by name in the narrative. The only incident that I found hard to swallow was when the judge in the book allowed a member of the jury to jump up and begin interrogating the so-called expert witness. I said to myself, “Wait a minute! You couldn’t do that in an American courtroom, and our legal system is based on the British one!” But apparently there are circumstances in which that might be allowed, at least in Britain.
Finally, keep in mind that absence of evidence is not the same thing as evidence of absence. Now who said that?
Ah yes, it was Carl Sagan.
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