Full- and part-time wage differences in Spain: an analysis along the wage distribution

The purpose of this paper is to examine wage differences between part- and full-time workers distinguishing by gender by using a large Spanish matched employer-employee data set and an econometric decomposition that permits to decompose wage differences by quantiles of the wage distribution.

The research is based on cross-section matched employer-employee microdata from a large representative survey (the Encuesta de Estructura Salarial) which is carried out with a harmonised methodology common to all European Union member countries and that has been designed specifically to provide reliable evidence about characteristics of the wage distribution such us wage differentials associated with the type of working time. From a methodological point of view, the econometric decomposition technique proposed recently by Fortin et al. (2011) to decompose wage differences between part-time and full-time workers by quantiles of the wage distribution is applied. This methodology has the advantage over similar techniques that provides a detailed decomposition of wage differentials and has not been used before to examine the wage impact of part-time jobs.

The results show that the significant raw wage gap that part-time workers experience in Spain differs substantially along the wage distribution. In the case of part-time females, the wage disadvantage is mostly explained by their relative endowments of characteristics (and particularly by their lower endowments of human capital and their segregation into low-wage sectors) but a significant wage penalty still persists, increasing along the wage distribution. In the case of males the wage disadvantage is only found in the lower part of the distribution and it is due both to their worst endowments of characteristics and a significant wage penalty.

The evidence for Spain shows that the part-time work tends to affect differently to the wages of males and females, with a higher part-time penalty for males, as predicted by the “flexibility stigma” hypothesis, and penalising low-qualified men in the lower part of the wage distribution and high-qualified women in the upper part of the distribution the most.

The analysis contributes to the literature by examining wage differences along the wage distribution for both genders using econometric decomposition methods, an aspect that to the authors’ knowledge has been examined only scarcely in the international literature with non-conclusive evidence and has not been examined in previous studies for the Spanish case. In this vein, Spain is a particularly interesting analysis case from an international perspective of the wage consequences of part-time jobs, given that in contrast with most other advanced countries a majority of part-time employment in this country is involuntary and this phenomenon is especially affecting disadvantaged groups.