The Monty Hall Problem
Three doors, one car. The host opens a losing door and offers you the swap. Does it make any difference whether you take it?
1975 (posed), 1990 (made famous)9 min read
American popular writing on reasoning
Marilyn vos Savant
1946
Columnist for Parade magazine. Her 1990 answer to the Monty Hall problem was correct and provoked roughly ten thousand letters of disagreement, around a thousand from readers holding doctorates — one of the best-documented episodes of collective expert error on a simple question.