'Sub-optimal' by chance: Insights from a long-term analysis of municipal area and population size

In the search of a better administrative efficiency, change in municipal boundaries and creation (or suppression) of local administrative units reflect a progressive adjustment to an increasingly variable spatial distribution of population. With intense population growth, municipal size is regarded as a proxy for amount (and spatial concentration) of services and infrastructures, being functionally related with agglomeration factors, land availability to building, and specific socioeconomic contexts. Based on these premises, the intrinsic relationship between settlement expansion, population growth, and municipal size in a metropolitan region of Southern Europe was investigated extensively in this study. A quantitative analysis of the relationship between population density and municipal area provides a pivotal knowledge to policy and planning adjustments toward a more balanced spatial distribution of population and administered land among local government units. Descriptive statistics, mapping, correlation analysis and linear regressions were used to assess the evolution of this relationship over a long time spam. Average municipal size in Athens decreased moderately over time with increasing spatial heterogeneity. Conversely, average population density per municipality increased even more rapidly with a considerable reduction in spatial heterogeneity. The observed goodness-of-fit of the linear relationship between population density and municipal area increased significantly over time. Empirical results of our study indicate that municipal size has progressively adjusted to population density across metropolitan areas, determining a more balanced spatial distribution of resident population, which was consolidated by the recent administrative reform of local authorities in Greece (the so called 'Kallikratis' law). Such conditions represent a base for informed analysis of the spatial structure of local administrative units and contribute to the debate on optimal size of municipalities and other administrative districts with relevant impact on both urban and metropolitan scales of governance.