An intelligence test sometimes shows a man how smart he would have been not to have taken it.

It is a heavily quoted principle at the Marshall School of Business. in time every post tends to be occupied by an employee who is incompetent to carry out its duties. He became widely famous in 1968 on the publication of The Peter Principle in which he states: "In a hierarchy every employee tends to rise to his level of incompetence.

Laurence Johnston Peter (September 16 1919 – January 12 1990) was an educator and "hierarchiologist" best known to the general public for the formulation of the Peter Principle.