Why Underperformers Think They’re Stars

You may not know about the Dunning-Kruger effect, but it explains how hard it can be to get underperforming employees to improve. The Dunning-Kruger effect is a cognitive bias that causes people to overestimate their own skill level and fail to recognize other's genuine skills. The effect occurs whether you're looking at physical skills (like playing tennis or golf) or mental skills (like reading comprehension or chess). In one study by David Dunning and Justin Kruger of humor, grammar, and logic, participants in the 12th percentile estimated that they were in the 62nd percentile.

Bryan Garner, in the March 2013 ABA Journal, used the effect to explain why lawyers who can't write well think that they can. Paul Krugman in the New York Times used it to explain "experts" whose economic predictions prove wrong time after time.