Two Views of the City as a Source of Space-Time Trends in Economic Development and the Decline of Human Fertility

The relationship between the spread of economic development and the spread in the decline of human fertility within a regional setting is examined. A two-equation recursive model is developed by means of Casetti's expansion method. The model is evaluated using county data for Oklahoma over the period 1940-1972. Two alternative indicators of economic development are used in the model , the proportion of the labor force employed in agriculture and per capita retail sales, to capture the effects of changes in production and consumption upon fertility. The results indicate that changes in agricultural employment have neither diffused nor become more polarized, but that retail sales became more polarized with respect to major urban centers during the period. The decline in fertility resulted largely from changes in economic development, which was a polarizing influence on the former. There was also, however, an independent spread effect upon the decline of fertility, giving rise to a situation in which major urban centers generate both polarized and diffused decline in fertility.