Revisiting demographic transition: correlation and causation in the rate of development and fertility decline

This study takes a retrospective look at the time course of total fertility rate (TFR) and per capita wealth among countries, relating it to family planning initiatives and other factors thought to influence either fertility or wealth. It was found that countries that implemented strong family planning programs achieved fertility reduction much faster and earlier than comparable countries that did not. Fertility decline typically preceded marked increases in wealth, but per capita wealth growth usually accelerated when fertility fell to between two and three births per woman. The negative relationship between TFR and GDP per capita tends to be deeply concave for those countries that have achieved low fertility. Higher fertility countries in the same region tend to follow a parallel course, but at a slower pace, and most with current fertility above three are yet to see sustained wealth increase. In the absence of significant income from oil or other resources, fertility reduction appears to be a necessary if not sufficient condition for sustained economic growth. Causation runs in both directions, with prosperity and development of education and health services enhancing the reduction in family size, but interventions to promote prosperity are less cost-effective in priming this cycle than interventions for fertility reduction.