The urban spatial change hypothesis revisited: A case study of Shanghai

The classical Urban Spatial Change (USC) hypothesis efficiently summarizes urban development patterns through population changes across space but faces disputes regarding its generality and applicability due to its reliance on empirical research primarily from Western contexts. This paper provides the most up-to-date examination of the complete trajectory of Shanghai's remarkable urban transition from a small county to the world's third-largest megacity over 177 years (1843–2020), based on long-term population spatial changes within the USC hypothesis framework. The findings suggest that while Shanghai generally follows the conventional USC trajectory of centralization, decentralization, and recentralization, it also exhibits notable heterogeneities. Those include the bypassing of disurbanization and highly compressed processes following a sequence of urbanization, suburbanization and reurbanization, strong government interventions accompanied by a complex and dynamic interplay between market forces, and a central role of inter-regional migrants throughout Shanghai's urban life cycle. The results support the view that while the USC hypothesis provides a generalized summary of urban systems and offers a concise overview of urban changes, further refinement is necessary to accurately capture the diverse trajectories across different types of cities.