Inequalities in the level of sustainable development in the European Union countries

The aim of the research is to assess the degree of differentiation of sustainable development in the European Union countries in 2015-2019 and to group EU countries by the level of sustainability. In order to achieve the stated goal, a linear and non-linear ordering of selected variables included in the four orders that constitute sustainable development: social, economic, environmental, as well as institutional and political, was carried out. As a result of linear ordering, four groups of countries were distinguished. The linear ordering procedure was preceded by the construction of a synthetic variable. Ward's hierarchical method, based on Euclidean distance, was used as a non-linear ordering method. The data used in the analysis came from the Eurostat database. The research carried out shows significant inequalities in the level of sustainable development of EU countries. This applies to sustainable development in the integrated approach and to the assessment of individual orders. The rankings of countries in each order differ significantly from each other, and the overall assessment of sustainable development shows the greatest correlation between economic, institutional, and political order. Research results show that the leaders in sustainable development include Sweden, Finland, Denmark, Austria, and Estonia. At the other pole are Greece, Bulgaria, Cyprus and Romania.