Polycentricity: The last episodes or the new season?

This article presents a systematic review of empirical studies on polycentric spatial structures at a regional scale in order to assess their effectiveness as prescriptive and normative models in spatial planning. The results show that very few studies have emphasised primarily the positive effects of polycentricity, while a large number have evaluated the performance of non-polycentric (monocentric) structures more positively. Our study shows that evaluating the effectiveness of polycentricity as a normative model is both theoretically and empirically challenging, and that polycentricity is still the subject of a research agenda with hypotheses that need to be tested. The findings indicate that polycentricity is not the superior model it has been frequently advertised as and that its effectiveness is significantly influenced by a range of factors relating to its political foundation, weak theoretical positioning, ambiguous conceptualisation, context dependence, and highly variable governance frameworks. The study recommends that scientific theorising of polycentricity should be aligned with close scrutiny of the relevant contexts to overcome its idealistic nature and lack of adaptability. The article cautions planners and policymakers against a sweeping promotion of polycentric development, as the implementation of this concept is not necessarily associated with fostering economic performance, social cohesion, and environmental sustainability.