Measuring upward convergence involves quantifying two concepts, improvement and convergence.
Improvement is usually measured through changes in unweighted averages of Member States’ performance on selected indicators. Unweighted averages are used to give each Member State, or geographical entities, the same representation and importance in determining the overall trend.
Convergence is measured as a decrease in inequalities or a catch up of least performing countries towards best performing Member States. Convergence could be measured in three different ways, each of which with its own political meaning:
- Beta convergence is used to measure whether countries starting from initially low performance levels grow faster than better performing countries. This process is referred to as catching up.
- Sigma convergence refers to the overall reduction in disparities among countries over time and is measured by the evolution of the statistical measures of dispersion, such as the standard deviation or the coefficient of variation. A decrease in the standard deviation or coefficient of variation over time indicates convergence.
- Delta convergence is used to analyse countries’ distance from the best performing country. Delta convergence is usually measured through the sum of the distances between the Member States and the top performer.
At the beginning of the 21st century, there was upward convergence between the EU Member States for most of the indicators considered in this analysis. However, social and economic indicators were strongly affected by the financial crisis of 2008, and during the subsequent economic crisis between 2008 and 2013 disparities between the EU Member States tended to increase. These disparities highlight the need for current efforts to bolster Member States’ resilience to economic shocks. It remains to be seen what possible impact COVID-19 will have on European societies in the long term and the implications of this for achieving upward convergence.