More Necessary and Less Sufficient: An Age-Period-Cohort Approach to over Education in a Comparative Perspective.

During the last 5 decades, tertiary educational attendance rates increased dramatically, both for men and women. In most countries, the demand for academic skills did not expanded at the same rate tertiary educational did, even during the information revolution. The U.S. debate between Richard Freeman (Overeducated American 1975) and Herbert Smith (Overeducation and Underemployment: An Agnostic Review 1986) was one of the first in a much contrasted international comparison of social trajectories: in many countries, some birth cohorts have been exposed to risks of over-education, or a decrease in returns to education.

In our paper we analyze LIS data on five contrasted western countries (US, Germany, France, Spain, Denmark) for cohorts born between the Second World War to more recent generations of young adults today. This dataset built on harmonized cross-sectional surveys, is combined with secondary data on skilled biased technological to study whether educational expansion reduced both relative and absolute returns to education. Using newly developed age-period-cohort gap models (taking into account the most recent debates on APC models), we are able to study whether the younger cohorts enjoy higher or lower returns to education than older cohorts. Our results suggest that generally, the increase of skill based sector was not enough to provide demand for the supply of tertiary education graduates, leading to a decrease in educational returns relative to older cohorts. However, the expansion of skill based sectors increased within-cohort inequality, especially increasing the gap between tertiary and secondary education graduates.