Trial by Mathematics

On a June morning in 1964, an elderly woman was shoved to the ground in a Los Angeles alley and her purse was snatched. No witness could positively identify the culprits, but the descriptions were vivid: a young woman with a blond ponytail who fled in a yellow car driven by a bearded, mustached Black man. The Defendant and his wife — an interracial couple who owned a yellow Lincoln — were arrested. Short on solid eyewitness identification, the Prosecution called a mathematics instructor to the stand. He assigned a probability to each observed trait — the yellow car, the ponytail, the beard, the interracial couple — multiplied them together, and told the jury the odds that any OTHER couple fit the description were one in twelve million. The Defense argued the courtroom had been turned into a probability lecture built on numbers pulled from thin air.