Expert Political Judgment: How Good Is It? How Can We Know? - New Edition

Philip E. Tetlock

Aug 2017 · Princeton University Press

About this ebook

Since its original publication, Expert Political Judgment by New York Times bestselling author Philip Tetlock has established itself as a contemporary classic in the literature on evaluating expert opinion.


Tetlock first discusses arguments about whether the world is too complex for people to find the tools to understand political phenomena, let alone predict the future. He evaluates predictions from experts in different fields, comparing them to predictions by well-informed laity or those based on simple extrapolation from current trends. He goes on to analyze which styles of thinking are more successful in forecasting. Classifying thinking styles using Isaiah Berlin's prototypes of the fox and the hedgehog, Tetlock contends that the fox--the thinker who knows many little things, draws from an eclectic array of traditions, and is better able to improvise in response to changing events--is more successful in predicting the future than the hedgehog, who knows one big thing, toils devotedly within one tradition, and imposes formulaic solutions on ill-defined problems. He notes a perversely inverse relationship between the best scientific indicators of good judgement and the qualities that the media most prizes in pundits--the single-minded determination required to prevail in ideological combat.


Clearly written and impeccably researched, the book fills a huge void in the literature on evaluating expert opinion. It will appeal across many academic disciplines as well as to corporations seeking to develop standards for judging expert decision-making. Now with a new preface in which Tetlock discusses the latest research in the field, the book explores what constitutes good judgment in predicting future events and looks at why experts are often wrong in their forecasts.

Ratings and reviews

The complaints from other reviewers are valid if statistics bother you, but you can skip the details and read profitably for the conclusions of each chapter and the summaries Tetlock gives of the numbers. The principal takeaways include the claim that predicting the future is terribly difficult, and no one model excels at it, in the field of foreign affairs at any rate. The models Tetlock offers are those of Isaiah Berlin's hedgehog, the deeply burrowing, single-minded specialist, and the fox, the person of wide but more general knowledge and experience in foreign affairs. It turns out the fox does better, but not necessarily better than a coin flip. While recently reading a biography of Talleyrand, I was able to understand the source of his insights in the forty-plus years of his work in the foreign affairs of France between the reigns of Louis XVI and Louis Philippe. He was widely read and observed rather than merely theorized about European nations' interests, like Tetlock's ideal fox. The book provides evidence to be skeptical of predictions by the experts, especially those who specialize in a particular country. It also illuminates their rhetoric in explaining their mistakes. I recommend the book highly.

About the author

Philip E. Tetlock is Mitchell Professor of Leadership at the University of California, Berkeley. His books include Counterfactual Thought Experiments in World Politics (Princeton).