Magazine article Population Briefs

End to Childbearing Delays Could Lead to Fertility Rise. (Demography)

Magazine article Population Briefs

End to Childbearing Delays Could Lead to Fertility Rise. (Demography)

Article excerpt

With fertility in much of the developed world at historic lows, a lively debate has emerged among demographers and policymakers: How low will it go? A study by demographer John Bongaarts, a Population Council vice president, tackles this question by analyzing the implications of changes in the timing of childbearing. The study concludes that fertility in many developed countries, especially those in the European Union, could soon rise somewhat.

Although fertility in the developed countries is low, Bongaarts believes that women's eventual childbearing levels will not be as low as the total fertility rate might suggest. This is due to a "postponement effect," which is the result of women delaying childbearing until later in life.

Low fertility

By the late 1990s, the conventionally measured fertility rate in the "more developed" world (Europe, North america, Japan, Australia, and New Zealand) had decreased to 1.6 births per woman--well below the level at which population size stabilizes, 2.1 births per woman. Low fertility may lead to extreme population aging, financial pressure on social security systems, and declining population size.

Fertility is usually measured as the total fertility rate (TFR), which equals the average number of births a woman would have if she were to bear children in each year of her life at the same rate as did women of that age in the year the TFR is calculated. It differs from the completed fertility rate (CFR), which is a longitudinal measure of the average number of children 50-year-old women in fact had. The CFR shows actual childbearing, but can only be determined after childbearing is complete. Although the CFR is more accurate, demographers prefer to use the TFR because it provides more up-to-date information on current trends in fertility.

Unfortunately, the total fertility rate can give a distorted view of fertility levels because it has been temporarily depressed by a rise in women's mean age at childbearing. In effect, when successive cohorts of women delay childbearing, births are spread out over a longer period than would be the case if they bore children at earlier ages. This effect renders the conventionally measured TFR difficult to interpret. (Conversely, if successive cohorts of women gave birth earlier than women had in the past, these births would accumulate more rapidly and thus temporarily inflate the TFR.)

"The postponement effect has been present in many developed countries since the 1970s, but this distortion is temporary," Bongaarts notes. …

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