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July 2002, Vol. 8, No. 1 Demography In a small number of developing countries fertility has dipped below the replacement level of 2.1 births per woman. Some demographers have asked whether projections of future population growth might be made more accurate by changing them to assume that fertility in the long run will fall below replacement in all countries, rather than to 2.1 births per woman as is now the assumption. If fertility declines to 2.1 births per woman, population will peak in the twenty-second century and then stabilize. If fertility declines to 1.8 or 1.9 births per woman, on the other hand, population will peak late in this century and then begin a slow decline. In March 2002, a United Nations expert group met to debate the possibility of revising the UN methodology for projecting the course of population growth over the next several decades. Population Council demographer John Bongaarts, one of the experts called to comment on this issue, contends that simply lowering the assumed ultimate fertility level would be insufficient. He recently published research outlining additional changes that would be needed to make the fertility projection model more accurate. “The UN has been tremendously successful at predicting population growth in the past, but a close look at their projections suggests several ways to improve them,” says Bongaarts. A slight reduction in the assumed fertility level at the end of the transition to about 1.9 is a step in the right direction. “Other adjustments are also desirable, although once the necessary adjustments are made, population projections into the middle of this century will still be similar to the current UN projections.” Pace of fertility transition In his recent study, Bongaarts examined trends and patterns in fertility in the developing world, focusing particularly on the later stages of transition. He sought to identify regularities in the past record that may provide clues to future trends. Bongaarts looked at UN estimates of total fertility rates between the years 1950 and 2000 for all countries of Africa, Asia, and Latin America and the Caribbean except Japan, Australia, and New Zealand. Past fertility trends have been highly variable. Some countries—Singapore and South Korea, for example—proceeded fairly swiftly to below-replacement-level fertility. Others, mostly in sub-Saharan Africa, still have high fertility. Rapid declines to below replacement are the exception rather than the rule. Three key features summarize these past transitions. First, fertility is high until the transition begins. Second, once the transition gets underway, fertility declines fairly rapidly. And third, the pace of decline decelerates as countries reach the later stages of the transition. Sometimes the fertility transition stalls above replacement level for decades. These same patterns are likely to prevail in the future, and they should be incorporated in projections. In the future many developing countries will experience slower declines than the UN now assumes. Bongaarts also looked at several indicators of development to see whether these had any bearing on the fertility transition. Some observers have argued that, despite conventional wisdom, development may play little role in reducing fertility. “The beginning of the fertility transition is often driven by the diffusion of new ideas about reproductive behavior among individuals, communities, and countries,” says Bongaarts. “Education, health, and literacy, however, are particularly crucial to the completion of the fertility transition. Wealth is less critical. Poor countries, such as Sri Lanka, with high levels of health and education can have low fertility.” Bongaarts’s investigation revealed that most developing countries that have attained near-replacement fertility levels have an average life expectancy of more than 70 years and a literacy level over 90 percent. The large majority of developing countries fall well short of this level of human development. Thus, considerable progress will likely have to be made before near-replacement fertility becomes widespread, Bongaarts contends. One reason that reaching replacement level fertility is difficult is that it requires a high degree of birth control. Diligent, effective use of family planning is needed to avoid unintended pregnancies. “A high-quality family planning program can move a country closer to replacement fertility than would be expected from its level of development alone,” explains Bongaarts. “But these programs alone cannot bring about declines in desired family size. Human development is the key to reducing preferences for large families and to completing the transition. Source Outside funding | |||||||||||||||||||||||||||||||||||||||||||||||
