A Common Prediction Mistake

Suppose you’re told that a man named John is extremely well-educated, smokes a pipe, and wears tweed jackets with patches on the sleeve—is he more likely to be a particle physicist or a janitor? A physicist, you immediately think. But you’d likely be wrong, because janitors are common and particle physicists rare. The chances that you’d happen upon a very well-educated, tweed wearing, pipe-smoking janitor are higher than those that you’d meet a physicist who meets the same profile.

Laurie Abraham writing in Slate