The Peter principle is a concept in management theory formulated by Laurence J. Peter and published in 1969. It states that the selection of a candidate for a position is based on the candidate’s performance in their current role, rather than on abilities relevant to the intended role. Thus, employees only stop being promoted once they can no longer perform effectively, and “managers rise to the level of their incompetence.”
Check out this really excellent read by Josh Clark.—>How the Peter Principle Works