Go figure

Can bad math undermine a democracy? An eye-opening look at the sloppy statistics and fuzzy figures that bombard and bamboozle us

September 26, 2010|Jordan Ellenberg, Globe Correspondent

The great Massachusetts comic Eugene Mirman has a routine about people who quote half-remembered statistics. He says he likes to tell those people that he read somewhere that 100 percent of Americans are Asian.

“But Eugene,” they say, “you’re not Asian.”

And the punchline, delivered with magnificent self-assurance: “I read that I was!”

Charles Seife’s spirited new book, “Proofiness,’’ is a nearly 300-page exposition of Mirman’s joke, which, per Seife, is on us. In every realm of life, from commerce to politics to health, we are being snookered by fake numbers, delivered with the false conclusiveness that only two or three decimal places and a percentage sign can impart. “If you want to get people to believe something really, really stupid,” Seife writes, “just stick a number on it.” “Proofiness’’ is a field guide to mathematical trickery, in the spirit of Darrell Huff’s classic “How to Lie with Statistics.’’ One hopes it will serve as a public inoculation against the malady it describes.

Seife’s targets are less ridiculous than Mirman’s, but sometimes only just. A British psychologist generated buzz in 2003 by releasing a “mathematical formula for happiness.” In 1992, an overzealous attachment to a linear statistical model led researchers to claim in the journal Nature that women marathoners would outrun men by 1998.

Seife defines proofiness as “the art of using bogus mathematical arguments to prove something you know in your heart is true — even when it’s not.’’ In its most pernicious form, it assigns exact numbers to inherently fuzzy quantities, as when an expert witness delivered a defendant to the chair by testifying he was “100 percent certain” the man would kill again; or as in the famous case of Sally Clark, sent to prison for murdering her children based in part on the testimony of a pediatrician that the probability of two cases of sudden infant death syndrome striking a single family was about 1 in 73 million.

In the same spirit, Seife revisits two disputed elections: the 2008 Minnesota Senate race between Al Franken and Norm Coleman, and the 2000 presidential election in Florida. Minnesota undertook a full recount to determine precisely which would-be senator had garnered a few thousandths of a percent more votes than the other; the exercise quickly degenerated into an absurd spectacle, in which distinguished lawyers were reduced to arguing over what to do about a ballot in which a voter both filled in the oval for Franken and wrote in the name “lizard people.’’ The Florida recount was just as close, and just as confused (featuring Pat Buchanan in that contest’s version of the lizard people).