Empirical evidence for the Peter Principle (or, why bosses are so incompetent)

Dr. Laurence J. Peter's 1969 "Peter Principle" holds that companies promote high-performing employees to more and more exalted managerial jobs until those employees reach a role that they're incompetent to perform, and thereafter, the employees' negative performance reviews mean that they stop getting promoted, so that, on average, managers are all stuck in jobs they're not very good at. Read the rest