PERSON
Philip Tetlock
Canadian-American psychologist (b. 1954) whose twenty-year study of expert prediction demonstrated that credentialed forecasters perform no better than chance — and whose fox-hedgehog distinction transformed how we understand judgment.
Philip E. Tetlock is the Annenberg University Professor at the University of Pennsylvania, holding appointments at both Wharton and the School of Arts and Sciences. Born in Canada, he received his PhD from Yale and spent formative years at UC Berkeley before moving to Penn. His landmark Expert Political Judgment (2005) documented that political and economic experts' predictions were no more accurate than random guessing, while a small minority of 'superforecasters' consistently outperformed both experts and statistical models. The distinguishing feature was not intelligence but cognitive style: foxes who knew many things outperformed hedgehogs who knew one big thing.
In The You On AI Field Guide
Tetlock's twenty-year longitudinal study (1984–2004) collected 28,000 predictions from 284 credentialed experts across political science, economics, and intelligence analysis. Each prediction was specific, time-bound, and probabilistic — designed to be scored with the precision of a ledger. The results were devastating to the cult of expertise: average expert accuracy approximated that of a dart-throwing chimpanzee. More damaging still, the