Socio-demographic patterns of instability: Essays on earnings and income volatility in Belgium

There has been growing concern over whether earnings have become less stable over time. These concerns have been fuelled by the deregulation and flexibilisation of labour markets, the increasing frequency and interconnectedness of financial crises, and questions surrounding the adequacy of welfare states. In response, an emerging body of literature has focused on measuring earnings and income volatility and examining the potentially adverse consequences associated with it.

This dissertation provides the first comprehensive analysis of long-term trends in earnings volatility in Belgium, a country characterised by both a compressed wage distribution and a high degree of labour market segmentation. The empirical analysis consists of three main chapters that examine the evolution of earnings volatility, its socio-demographic correlates, and the importance of policy timeliness.

The first two chapters draw on a novel linked administrative dataset covering the entire Belgian population from 2005 to 2021, combining tax records with detailed socio-demographic information. The first chapter examines earnings dynamics and trends in inequality. Investigating whether the nature of inequality has shifted over time, the findings suggest that inequality is increasingly characterised by earnings instability rather than persistent disparities. The chapter further explores how these developments differ by gender and educational attainment.

The second chapter, divided into two parts, focuses on measurement issues and the earnings volatility gap between migrants and natives. It also investigates heterogeneity within migrant groups and the factors driving differences in volatility. Education again emerges as an important explanatory factor, although a substantial share of the gap remains unexplained.

The final chapter adopts an intra-year perspective, using nowcasting and microsimulation techniques to assess the timeliness and effectiveness of differently targeted social policies in cushioning income shocks and preventing poverty during the COVID-19 pandemic. The results indicate that automatic stabilisers, such as temporary unemployment benefits, were more timely and effective than discretionary policy measures.

Overall, the findings of this dissertation reveal a more dynamic picture of inequality where women, lower-educated individuals, and individuals with a migration background are disproportionately exposed to earnings instability. The dissertation therefore underscores the importance of continued monitoring of these trends, calling for policy interventions aimed at addressing the structural inequalities that hinder labour market inclusivity.

Recommended citation: Wizan, M. (2026). Socio-demographic patterns of instability: Essays on earnings and income volatility in Belgium. [Doctoral dissertation, University of Antwerp]. https://doi.org/10.63028/10067/2255400151162165141
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