In an effort to determine the roots of accuracy and inaccuracy in forecasting, the American political psychologist Philip E. Tetlock and his assistants collected 27,451 predictions on world politics between 1988 and 2003 from 284 “experts” in universities, governments, think tanks, foundations, international institutions, and the media. Replete with tables, graphs, and equations, Tetlock’s 2005 book, Expert Political Judgment,
