Diploma disease is a term developed by Ronald Dore as part of a critique of the excessive reliance on the selection process in formal educational institutions (and hence on educational qualifications) as evidence of ability, training, and merit for entry to particular occupations, careers, or internal labour-markets. This phenomenon is sometimes referred to as credential inflation. As an unintended consequence of the belief that educational certificates are the key to obtaining the best-paid and most secure jobs, individuals may come to strive for constantly higher credentials in order to procure jobs which previously did not demand these, and for which their education does not in any case prepare them. Education thereby becomes merely a ritualistic process of accumulating qualifications.
— from encyclopedia.com