Accounting for changes in the Spanish wage distribution: the role of employment Composition effects

Despite a rapid decrease in unemployment and strong GDP and employment growth, real wages barely increased in Spain over the period 1995-2006. An explanation of this lack of growth may rely on employment composition effects derived from structural changes, such as the rise in the weights of employment in the construction and services sectors, the increase in female employment participation, and the arrival of large immigration inflows. Using data from three waves of the Structure of Earnings Survey, we break down observed wage changes into those due to varying worker and job characteristics and variations of the returns to those characteristics. Quantile regressions are used to estimate wage equations at different percentiles and to construct the counterfactual wage distributions that would have been observed had individual and job characteristics remain constant over time. Our main finding is that the lack of growth of Spanish real wages over the period 1995-2006 is mainly due to the decrease of returns to characteristics, specially education and labour market experience, which is more noticeable at the upper deciles of the wage distribution, and not to changes in employment composition, which when taken over a wide set of worker and job characteristics, had positive effects on wages.