Intrafirm human capital externalities and selection bias

This article investigates the existence of intrafirm human capital externalities in the Spanish economy. In doing so, it focusses on two estimation issues. First, a semiparametric methodology is used to estimate externalities in a more flexible way that allows to affect all parameters in the equation. Second, two approaches to control for selection bias are designed for use in cross-section data. Our results show a higher externality effect on wages when using the semi parametric approach as compared to the standard estimation approach. Additionally, the estimations even when controlling for selection bias give evidence of externalities. © 2011 Taylor & Francis.