Kruger and Dunning observed how perception of personal competence digressed from reality, especially in the incompetent.
A person who is unskilled in a domain may:
(1) believe that s/he is competent and capable
(2) make mistakes because of this incompetence
(3) be unable to recognize that s/he was responsible or what caused the failure
At the other end of the spectrum, a person who is skilled in a domain may:
(1) realize that s/he is ignorant
(2) hesitate to act
(3) be able to recognize his/her role in a problem
The problem can be compounded in organizations that promote problem people up and out.