The article introduces a new way to analyze income convergence called marginal vertical convergence. By looking at individual contributions of countries to the overall process of leveling out income, the researchers found that while the European Union as a whole showed income convergence from 1993 to 2018, the speed and extent of convergence varied between member states. This variation was due to differences in economic growth, resilience to economic shocks, and levels of income inequality. Removing outliers improved the accuracy of the models used in the analysis.