Rural and urban population changes and the stages of economic development: a unified approach.

The long-term aspects of the process of economic development and urbanization are examined. A model is presented that shows the dynamics of economic development from the earliest to the more advanced stages. "The model is able to explain not only the occurrence of a downturn in the rural population after the initial phase of population growth both in rural and urban areas, but also the delayed occurrence of such a downturn in many present-day developing countries. The author then focuses [on] the later stages of economic development and explains two alternative courses of urbanization, namely, the reversal process and the continual-growth process, as special cases of the general model; which of the courses occurs depends on the value of the elasticity of urban agglomeration-economies."