According to manpower requirements economists, "overeducation" occurs when an individual has more schooling than is "required" by their job. Studies have found that men (but not women) who exceed the schooling norm for their job by 4 or more years are more dissatisfied with their current job and more likely to look for a better one, but that they are not more likely to be politically alienated or to support left wing causes. Individuals whose schooling achievement (competence in reading and math) exceeds the norm for their job are significantly more productive than coworkers. This implies that a greater supply of well educated workers will increase productivity even if available jobs do not change.
"Overeducaton" also refers to situations where highly educated workers are oversupplied relative to the norms of the past. These periods tend to be temporary because the circumstances which cause them are temporary and because the resulting decline in the wage premium for schooling causes a slowdown in the growth of university attendance which with some lag brings supply and demand back into balance.
The third use of these terms is to refer to a chronic tendency of a society to overinvest (or underinvest) in education relative to some social standard. Those who believe overeducation is chronic apply a "Does your job require it" standard, which reflects a very narrow conception of education. When, however, people's non-pecuniary tastes for higher learning, the tendency of the market to under reward expertise and the spillover benefits generated by scientists and artists trained in university are taken into account, most societies are chronically undereducated not overeducated.
Available at: http://works.bepress.com/john_bishop/33/