The OECD definition of functional urban areas (FUAs) capture meaningful connections between cities and their surrounding areas. The degree of urbanisation provides a definition of cities based on population density and cell contiguity. The FUA definition expands city boundaries to include areas economically connected through workplace commuting. The definition uses population density and travel-to-work flows as key information.
OECD Definition of Cities and Functional Urban Areas
Cities concentrate a considerable share of population and economic activity in OECD countries. Comparing cities across countries requires appropriate geographical definitions that also take into account the areas of influence of cities.