Output datasets of MA thesis based on ParlGov 2010-2024 data (Kopytsiak, 2025)

The collapse of left-wing authoritarian regimes in Central and Eastern Europe initiated a transformative journey toward democratization and European integration. However, the legacy of these regimes continues to shape party competition decades later. While previous studies have explored structural and institutional consequences, the long-term impact on the dispersion of parties along the left–right scale remains understudied. Using ParlGov Releases (2010– 2024) and focusing exclusively on EU member states, this thesis analyzes party system polarization (Dalton Polarization) and the ideological center of gravity (Country Ideology), and introduces a novel variable – Right-Wing Concentration (RWC) – to capture the simultaneous rightward shift and ideological narrowing. The study shows that in post-communist democracies, the far left is marginalized without a compensating far-right ascent, resulting in more right-leaning and less polarized party systems compared to consolidated democracies. This pattern intensifies over time within the studied period. By comparing countries with and without left-authoritarian legacies, the study demonstrates that historical background outperforms conventional structural variables in explaining ideological party configurations. These findings underscore the enduring imprint of authoritarian legacies and highlight the need for future research on party polarization in the EU to account for historical determinants alongside institutional, structural, and political factors.