In 1999, an English solicitor named Sally Clark went on trial for the murder of her two infant sons. She claimed both succumbed to sudden infant death syndrome. An expert witness for the prosecution, Sir Roy Meadow, argued that the odds of SIDS claiming two children from such an affluent family were 1 in 73 million, likening it to the odds of backing an 80-1 horse in the Grand National four years in a row and winning every time. The jury convicted Clark to life in prison.
But the Royal Statistical Society issued a statement after the verdict insisting that Meadow had erred in his calculation and that there was “no statistical basis” for his stated figure. Clark’s conviction was overturned on appeal in January 2003, and the case has become a canonical example of the consequences of flawed statistical reasoning.
Carol Dweck wrote Mindset: The New Psychology of Success, where she discusses the difference between a fixed mindset and a growth mindset. The fixed mindset believes that traits such as talent or intelligence are static, whereas a growth mindset believes that you can always get better.