As a group the pundits did worse than a random number generator.
Tetlock also found that specialists are not significantly more reliable than non-specialists in guessing what is going to happen in the region they study. Knowing a little might make someone a more reliable forecaster, but Tetlock found that knowing a lot can actually make a person less reliable.
. . . .
The experts' trouble in Tetlock's study is exactly the trouble that all human beings have: we fall in love with our hunches, and we really, really hate to be wrong. . . .
Tetlock's experts were also no different from the rest of us when it came to learning from their mistakes. Most people tend to dismiss new information that doesn't fit with what they already believe. Tetlock found that his experts used a double standard: they were much tougher in assessing the validity of information that undercut their theory than they were in crediting information that supported it.
[Tetlock believes] that he discovered something about why some people make better forecasters than other people. It has to do not with what the experts believe but with the way they think. Tetlock uses Isaiah Berlin's metaphor from Archilochus, from his essay on Tolstoy, "The Hedgehog and the Fox," to illustrate the difference. He says:
Low scorers look like hedgehogs: thinkers who "know one big thing," aggressively extend the explanatory reach of that one big thing into new domains, display bristly impatience with those who "do not get it," and express considerable confidence that they are already pretty proficient forecasters, at least in the long term. High scorers look like foxes: thinkers who know many small things (tricks of their trade), are skeptical of grand schemes, see explanation and prediction not as deductive exercises but rather as exercises in flexible "ad hocery" that require stitching together diverse sources of information, and are rather diffident about their own forecasting prowess.
A hedgehog is a person who sees international affairs to be ultimately determined by a single bottom-line force: balance-of-power considerations, or the clash of civilizations, or globalization and the spread of free markets. A hedgehog is the kind of person who holds a great-man theory of history, according to which the Cold War does not end if there is no Ronald Reagan. Or he or she might adhere to the "actor-dispensability thesis," according to which Soviet Communism was doomed no matter what. Whatever it is, the big idea, and that idea alone, dictates the probable outcome of events. For the hedgehog, therefore, predictions that fail are only "off on timing," or are "almost right," derailed by an unforeseeable accident. There are always little swerves in the short run, but the long run irons them out.
Foxes, on the other hand, don't see a single determining explanation in history. They tend, Tetlock says, "to see the world as a shifting mixture of self-fulfilling and self-negating prophecies: self-fulfilling ones in which success breeds success, and failure, failure but only up to a point, and then self-negating prophecies kick in as people recognize that things have gone too far."
Tetlock did not find, in his sample, any significant correlation between how experts think and what their politics are. His hedgehogs were liberal as well as conservative, and the same with his foxes. (Hedgehogs were, of course, more likely to be extreme politically, whether rightist or leftist.) He also did not find that his foxes scored higher because they were more cautious—that their appreciation of complexity made them less likely to offer firm predictions. Unlike hedgehogs, who actually performed worse in areas in which they specialized, foxes enjoyed a modest benefit from expertise. Hedgehogs routinely over-predicted: twenty per cent of the outcomes that hedgehogs claimed were impossible or nearly impossible came to pass, versus ten per cent for the foxes. More than thirty per cent of the outcomes that hedgehogs thought were sure or near-sure did not, against twenty per cent for foxes.
Why did I like Iverson's post? Confirmation bias probably.
Skeptic