Estimating Labour Market Discrimination with Selectivity Corrected Wage Equations: Methodological Considerations and an Illustration from Israel

This paper presents a modified and improved methodology for the decomposition of wage differentials between two groups of workers into an endowment component and a discrimination component. The standard decomposition technique does not take into account different probabilities of entering the profession under discussion. To incorporate this type of segregation into the wage differential decompositions, two statistical methodologies are merged: the Oaxaca methodology and the Heckman selectivity bias correction procedure. Using information derived from the entrance equations, the decomposition procedure is then modified, in order to take into account the contribution of segregation to the endowments and the discrimination components. It appears that there is more than one way to do it. The proposed methodology is applied to the analysis of wages of professionals in the Israeli labour market. Comparisons are made between the two genders and between Westerners and Easterners. Our results show that discrimination plays a more important role in explaining gender wage differentials than in explaining ethnic wage gaps and that selectivity corrected decompositions are quite capable of yielding very different conclusions than those based on the standard decompositions.