In 1969, Laurence Peter and Raymond Hull coined the expression 'the Peter Principle,' which is the theory that all employees will eventually hit a point in the organisational hierarchy where they are no longer fit to do their job. The idea started out as a lighthearted observation, but this is the reasoning behind it: all employees, when they are good at their job, will get promoted eventually. They'll carry on getting promoted until they reach a point where they are no longer good at their job.