World Development Report


CHAPTER 1:density

As countries become richer, economic activity becomes more densely packed into towns, cities, and metropolises.This chapter introduces density, the first of the geographic dimensions of development,defi ned as the economic mass or output enerated on a unit of land.Surveying the evolution of density with development, the chapter presents stylized facts about how density in a country rises with urbanization,rapidly at first, and then more slowly. These changes are associated initially with a divergence of living standards between places with economic density and
those without, later with a convergence. Living standards thus eventually converge between areas of different density, such as urban and rural.

The main findings:
1)The concentration of economic activity rises with development.
2)Rural-urban and within-urban disparities in welfare narrow with development.
3)Neither the pace of urbanization nor its association with economic growth is unprecedented.

Density refers to the economic mass per unit of land area, or the geographic compactness of economic activity. It is shorthand for the level of output produced—and thus the income generated—per unit of land area. It can, for example, be measured as the value added or gross domestic product (GDP) generated per square kilometer of land. Given that high density requires the geographic concentration of labor and capital, it is highly correlated with both employment and population density. Density is the defi ning characteristic of urban settlements.

Density, defined as GDP in purchasing power parities per square kilometer, rises with the level of development, and the densest places in the world are in the richest countries. Dublin, London, Paris, Singapore, and Vienna ranked at the top, in 2005, with more than $200 million in gross product per square kilometer.

A hierarchy of density.
A country’s urban hierarchy is characterized by two robust...