the Peter principleˈPeter ˌprinciple, the especially humor the idea that each person who works in an organization gradually moves up to higher and higher levels, until they reach their own ‘level of incompetence’ (=the level at which they are no longer able to do their job well). They then remain at this level for the rest of their working life, and this has a bad effect on their own work and on their organization. The idea was invented by the Canadian writer and teacher Laurence Peter.