Into the kaleidoscopic urbanization of Southern Europe: Modelling ‘form-function’ relationships through partial least squares regression

The present study implements a novel (exploratory) multivariate analysis' design to identify latent trends in long-term metropolitan growth, aiming to test patterns and processes of suburbanization in three mega-cities representative of the Southern European Mediterranean region. More specifically, a Partial Least Square (PLS) regression of 50 indicators, assessing the three pillars of sustainability, was conducted to explore the relationships among socioeconomic functions, urban form, and natural amenities in Athens, Barcelona, and Rome. The results reveal a consistent ‘form-function’ relationship across these Mediterranean cities, which reflects similarities in their landscapes and regional development paths. However, the analysis also highlights significant local variations, particularly in terms of economic polarization and social diversification, with more pronounced disparities observed in Athens, and decreasing in intensity from Rome to Barcelona. The study confirms that municipalities serve as an effective spatial unit for investigating these dynamics, outlining the role of demographic differences, economic specialization, and place-specific (non-economic) factors in shaping both social homogenization and diversification processes. These insights have important implications for spatial planning and policy-making, particularly in developing strategies that address local disparities while promoting balanced metropolitan growth and sustainable cities.