Questioning Polycentric Development and its Effects. Issues of Definition and Measurement for the Italian NUTS-2 Regions

Polycentric development is a widely used term both in academic research and in the normative agenda. However, its theoretical foundations and economic implications are still unclear and the concept of polycentricity still does not have a shared definition or a shared measurement method. The aim of this study is two-fold. First, it defines and measures polycentricity at a NUTS-2 regional level, by comparing functional and morphological methods. Second, in the light of the role assigned to polycentric development in terms of policy, the study investigates the relationships between the degree of regional polycentricity and the key economic variables of performance, namely, competitiveness, social cohesion and environmental sustainability. Our main finding was that functional and morphological methods lead to similar results. In addition, we find a correlation between polycentricity and a more unequal income distribution and a higher level of productivity, especially when polycentricity was measured in functional terms. No stable correlations were found between polycentricity and measures of environmental sustainability, such as land consumption and greenhouse gas emissions.