Capital humano heterogéneo y productividad de los graduados
The effects of human capital accumulation on productivity are analyzed both theoretically and within a unique sample of European higher education graduates. The levels of a set of competencies they used at work, plus the type of institution and study field they graduated from, are included as indicators of heterogeneity in a model for individual income which also controls for specific job/individual characteristics. The results show: first, that both type of institution and study field influence the market value of graduates' human capital; and second, that certain competencis are better rewarded than other, suggesting that productivity gains emerge preferentially from specific attitudes towards work.
In a recent paper, Garcia-Mainar and Montuenga-Gomez [Garcia-Mainar, I. \& Montuenga-Gomez, V. M. (2005). Education returns of wage earners and self-employed workers: Portugal vs. Spain. Economics of Education Review, 24(2), 161-170] apply the generalized IV model of Hausman and Taylor to estimate education returns of wage earners and the self-employed in Portugal and in Spain. Our examination reveals several problems which relate to the validity and documentation of the instrumental variables, as well as the robustness of the results.