The Efficiency of Economic Growth for Sustainable Development—A Grey System Theory Approach in the Eurozone and Other European Countries

This article builds upon the authors’ previous work on the Synthetic Efficiency Indicator for Economic Growth (SEI-EG), demonstrating the process of transforming economic-growth-related inputs into sustainable development outcomes. This innovative application of the SEI-EG provides a fresh perspective on the effects of eurozone membership on the sustainability efficiency of EU countries, thereby enriching the discourse on economic integration and sustainability efforts within the European Union. By integrating the economic dynamics of the euro area with environmental efficiency metrics, this study offers novel insights into the potential influence of currency union membership on achieving sustainable development goals. Covering the entire European Union, categorized by euro area and non-euro area membership, this study navigates through the risks to sustainability posed by global crises and the ongoing debate over the euro’s integration success and setbacks. Conducted from 2019 to 2021 using grey system theory, this research incorporates a revised set of seven indicators in the domain of industry, innovation, and infrastructure as recommended by the Europe 2020 project. The findings confirm the initial hypothesis that countries outside the euro area tend to exhibit higher efficiency as measured by the SEI-EG indicator. This article is composed of five parts. The first two parts present characteristic features of economies in the euro area and non-euro area, along with a critical trend in the latest literature on the benefits and risks of economic integration. The subsequent sections introduce the methodology for determining the indicator and the authors’ own corrections to it as well as the results of the research and a discussion.