Public Choice Mechanisms in Social Expenditure: Dynamics of Interest Groups, Voters, and Politicians

This paper empirically analyzes the increase in social expenditure in OECD countries, focusing not only on demographic aging and economic factors but also on political and institutional factors, particularly the public choice mechanism involving the interaction among interest groups, voters, and politicians. Using panel data from 2010 to 2023, the empirical results indicate that Voice and Accountability—encompassing citizen participation, freedom of expression, and government accountability—has a statistically significant positive effect on social expenditure. In addition, population aging is confirmed as a structural and persistent driver of the expansion of social spending, while the COVID-19 pandemic period is associated with a statistically significant increase in such expenditures. The findings suggest that social welfare policy should be understood not merely as a tool for protecting vulnerable groups, but as a political and economic outcome shaped by the interaction of political actors.