Nick Shulz interviews Philip Tetlock, the Mitchell Professor of Leadership at the University of California, Berkley, and the author of Expert Political Judgment, How Good Is It? How Can We Know, in What Makes You an Expert?:
And one of the first things we discover is that there is a tendency for experts to claim to know more than they do about the future. So if you look at all those predictions that are assigned 90 percent confidence, you’ll find out that events assigned 90 percent confidence don’t happen 90 percent of the time. Depending on the sub-group of experts we’re talking about, it can happen somewhere between 80 and 60 percent of the time.