Earnings inequality patterns: A comparative analysis of France, Italy, Portugal and Spain

In recent decades, inequality has become a central concern in both academic research and policy debate. This paper examines gross individual earnings inequality among employed workers in four European countries - France, Italy, Portugal, and Spain - using EU-SILC microdata for 2010, 2014, and 2019. Rather than relying on a single indicator of inequality or a narrow set of explanatory variables, we adopt a multidimensional empirical framework that considers multiple inequality measures and integrates a broad range of hypothesized correlates within a unified analytical setting. Methodologically, we combine Recentered Influence Function (RIF) regressions with a RIF-based Oaxaca-Blinder decomposition in order to analyse both the cross-sectional correlates of inequality and the role of compositional changes over time. The results show substantial cross-country heterogeneity. Variables associated with Skill-Biased Technological Change and broader processes of structural transformation emerge as important correlates of earnings inequality, but their relevance and configuration vary markedly across national contexts. By contrast, labour-market fragmentation appears as a more general pattern: atypical employment arrangements, especially temporary and part-time work, are consistently associated with higher levels of earnings inequality in all four countries. Overall, the findings suggest that earnings inequality is shaped by multiple, overlapping, and country-specific processes, rather than by common and homogeneous mechanisms. The analysis identifies statistical associations rather than causal effects, but it offers a comparative account of the institutional and structural correlates of inequality across the four economies examined.