There was a book written in 1969 called The Peter Principle. The authors claimed that people in a hierarchy rise until they finally reach their level of incompetence. In other words, people get promoted until they finally fail. According to Wikipedia, this is due to the fact that“.. skills in one job do not necessarily translate to another.” Peter Drucker (not the author of the Peter Principle) also addressed this issue.
Drucker wondered how someone who had been competent in their work for years could suddenly become incompetent. Much like the quote above, Drucker concluded that people do not suddenly become incompetent. They are applying the wrong skills and techniques to the new job. They are doing the wrong things in the new job. They are trying to use what had made them successful in previous positions to the new position. Drucker suggests “When you enter a new assignment, ask ‘What new things should I be doing in my new assignment to be effective?’”
May need some management help
Not every employee is going to be able to define what they are doing wrong or need to do differently. Their manager, recognizing their employee is failing, should counsel and guide that employee toward what skills are necessary to be effective. Often these skills may deal with issues of communication in their new job. Regardless, managers need to be attuned to how well recently promoted employees are doing in order to prevent that previously competent employee from now being labeled as incompetent.