Superforecasting: The Art and Science of Prediction

by Philip E. Tetlock

A confident yes or no is satisfying in a way that maybe never is, a fact that helps to explain why the media so often turn to hedgehogs who are sure they know what is coming no matter how bad their forecasting records may be. Of course it’s not always wrong to prefer a confident judgment. All else being equal, our answers to questions like “Does France have more people than Italy?” are likelier to be right when we are confident they are right than when we are not. Confidence and accuracy are positively correlated. But research shows we exaggerate the size of the correlation. For instance, people trust more confident financial advisers over those who are less confident even when their track records are identical. And people equate confidence and competence, which makes the forecaster who says something has a middling probability of happening less worthy of respect. As one study noted, people “took such judgments as indications the forecasters were either generally incompetent, ignorant of the facts in a given case, or lazy, unwilling to expend the effort required to gather information that would justify greater confidence.”10