The Origins of Scaling in Cities

TLDR

Cities are increasingly important, yet scientific understanding and practical management remain limited because they are complex, interdependent social, economic, infrastructural, and spatial systems that vary across vast scales. The study aims to show that all cities evolve according to a few local principles. The authors developed a theoretical framework of scaling relations to predict cities’ average social, spatial, and infrastructural properties. The predictions were confirmed across thousands of cities worldwide, and urban efficiency—balancing socioeconomic outputs and infrastructure costs—was found to be size‑independent, offering a potential metric for evaluating planning strategies.

Abstract

Despite the increasing importance of cities in human societies, our ability to understand them scientifically and manage them in practice has remained limited. The greatest difficulties to any scientific approach to cities have resulted from their many interdependent facets, as social, economic, infrastructural, and spatial complex systems that exist in similar but changing forms over a huge range of scales. Here, I show how all cities may evolve according to a small set of basic principles that operate locally. A theoretical framework was developed to predict the average social, spatial, and infrastructural properties of cities as a set of scaling relations that apply to all urban systems. Confirmation of these predictions was observed for thousands of cities worldwide, from many urban systems at different levels of development. Measures of urban efficiency, capturing the balance between socioeconomic outputs and infrastructural costs, were shown to be independent of city size and might be a useful means to evaluate urban planning strategies.