On polarization and mobility

Working Paper 2009-138

Abstract

This paper attempts to combine the analysis of wage (income) polarization with that of wage (income) mobility. Using the polarization index PG recently proposed by Deutsch et al. (2007) it shows that, when taking the identity of the individuals into account (working with panel data), a distinction can be made between a change over time in polarization that is the consequence of "structural mobility" (change over time in the overall, between and within groups inequality) and a change in polarization that is the sole consequence of "exchange mobility" (changes over time in the ranks of the individuals). This approach is then applied to the 1985-2003 Work Histories Italian Panel (WHIP), an employer-employee linked panel database developed by the Italian Social Security administrative sources. The empirical investigation attempts to improve our understanding of labor market segmentation in Italy, whether the groups are defined on the basis of the individual wages or derived from other criteria such as white versus blue collar workers.

Authors: Ambra Poggi , Jacques Silber.