Agglomeration Index : Towards a New Measure of Urban Concentration

Abstract

A common challenge in analyzing urbanization is the data. The United Nations compiles information on urbanization (urban population and its share of total national population) that is reported by various countries yet there is no standardized definition of "urban." This situation is particularly troublesome if one wishes to conduct a cross-country analysis or determine the aggregate urbanization status of regions (such as Asia or Latin America) and the world. This paper proposes an alternative measure of urban concentration that we call an agglomeration index. It is based on three factors: population density, the population of a "large" urban center, and travel time to that large urban center. The main objective is to provide a globally consistent definition of settlement concentration to enable cross-country comparative and aggregated analyses. As an accessible measure of economic density, the agglomeration index lends itself to the study of concepts such as agglomeration rents in urban areas, the �thickness� of a market, and the travel distance to such a market with many workers and consumers. With anticipated advances in remote sensing technology and geo-coded data analysis tools, the agglomeration index can be further refined.