Overeducation and Individual Heterogeneity

In this paper, the efficiency of human capital investments is evaluated in the light of inadequate educational careers and skill obsolescence. Assuming heterogeneous returns to schooling and overeducation we use the potential outcome approach to measure the causal effect of human capital investments on earnings as a continuous treatment effect. Empirical evidence is based on a sample of West German full-time employed males from the "BIBB/IABStrukturerhebung 1998/99". Our estimate of the average treatment effect of an additional year of schooling (ATE) amounts to 8.7%, which does not differ much from conventional instrumental variable estimates. For skilled and high skilled workers, we find no evidence that the average returns to overeducation are lower than the average returns to required educuation, which differs from the evidence find in most traditional studies. There is evidence for considerable heterogeneity in the expected returns to overeducation. For 20 to 30% of the workers returns seem to be negative.