Superforecasting: The Art and Science of Prediction

by Philip E. Tetlock

In 1954, a brilliant psychologist, Paul Meehl wrote a small book that caused a big stir.12 It reviewed twenty studies showing that well-informed experts predicting outcomes—whether a student would succeed in college or a parolee would be sent back to prison—were not as accurate as simple algorithms that added up objective indicators like ability test scores and records of past conduct. Meehl’s claim upset many experts, but subsequent research—now more than two hundred studies—has shown that in most cases statistical algorithms beat subjective judgment, and in the handful of studies where they don’t, they usually tie. Given that algorithms are quick and cheap, unlike subjective judgment, a tie supports using the algorithm. The point is now indisputable: when you have a well-validated statistical algorithm, use it.