You must read ...
New Yorker. December 5 issue. Page 98. Louis Menand, "Everybody's an Expert: Putting Practitioners to the Test." The article is a lengthy review of the book Expert Political Judgement: How Good Is It? by psychologist and Berkeley Professor Philip Tetlock. The apolitical treatise is based on 20 years' research on the predictive skill of experts.
In short, and doing neither the book nor the review justice, the "experts" are less likely to be correct than predictions based on coin tossing! Menand: "Tetlock has found that specialists are no more reliable than non-specialists in predicting what is going to happen in the region they study. Knowing a little may make someone a more reliable forecaster, but Tetlock found that knowing a lot can actually make a person less reliable." Tetlock: "We reach the point of diminishing marginal predictive returns for knowledge disconcertingly quickly." The devil is in the details—and the subsequent details make this piece a must read.
(FYI, I have long felt that the #1 thing Bob Waterman and I had going for us when we studied "excellent companies" was a certain naïveté or freshness. And I admit to wondering over the years whether my "enhanced knowledge" has actually hurt. I suspect that I'm at my best when I'm "half naïve"—e.g., on the topic of women and markets a couple of years ago; design, a couple of years before that.)