The value of national sample survey data relating to birth expectations for projecting births is reassessed in the light of data limitations pointed out by Ryder and Westoff among others and of the methods of projection used by the United States Bureau of the Census. The annual level of fertility under the cohort-fertility projection method depends on the assumptions regarding completed fertility, about which the available survey data are fairly informative, and on the assumptions regarding the timing of births, about which the survey data tell us very little. Test calculations suggest that Ryder and Westoff have overstated the significance of timing relative to completed family size for the level of future births. We believe that the fall in the annual total fertility rate in the first half of the sixties is to be explained only in part by a general delay in childbearing; a moderate to substantial decrease in completed family size has also occurred. Analysis of the latest set of fertility projections of the Census Bureau also suggests that the assumptions about completed fertility are a much more important determinant of the level of future births than timing, both in the short and long term. Although the available expectations data cannot help in predicting short-term annual changes in fertility, they appear useful for making long-term projections of annual fertility. Expansion of the size, frequency, and content of the sample surveys and incorporation of parity and birth interval into the projection method may improve projections.
This is a preview of subscription content, access via your institution.
Akers, Donald S. 1965. Cohort fertility vs. parity progression as methods of projecting births, Demography 2: 414–428.
Blake, Judith. 1966. Ideal family size among white Americans: A quarter of a century’s evidence. Demography 3: 154–173.
—. 1967. Family size in the 1960’s—a baffling fad? Eugenics Quarterly 14: 60–74.
Coale, A. J., and C. Y. Tye. 1961. The significance of age-patterns of fertility in high fertility populations. The Milbank Memorial Quarterly 39: 631–646.
Freedman, R., P. K. Whelpton, and A. A. Campbell. 1959. Family Planning, SteriIity, and Population Growth. New York: McGraw-Hill.
—, L. C. Coombs, Larry Bumpass, 1965. Stability and change in expectations about family size: A longitudinal study. Demography 2: 250–275.
—, and Larry Bumpass. 1966. Fertility expectations in the United States: 1962–1964. Population Index 33: 181–197.
Grabill, Wilson H., and Maria Davidson. 1968. Recent trends in child-spacing by American women. Demography 5: 212–225.
Goldberg, D., H. Sharp, and R. Freedman. 1959. The stability and reliability of expected family size data. Milbank Memorial Fund Quarterly 37: 370–385.
Ryder, Norman B. 1964. The process of demo-graphic translation. Demography 1: 74–82.
—, and Charles F. Westoff. 1967. The trend of expected parity in the United States; 1955, 1960, 1965. Population Index 33: 153–168.
United States Bureau of the Census. 1958. Illustrative Projections of the Population of the United States, by Age and Sex, 1960 to 1980. Current Population Reports, Series P25, No. 187.
United States Bureau of the Census. 1962. Projections of the Population of the United States, by Age and Sex, 1964 to 1985. Current Population Reports, Series P25, No. 286.
United States Bureau of the Census. 1967. Projections of the Population of the United States, by Age, Sex, and Color to 1990, with Extensions of Population by Age and Sex to 2015. Current Population Reports, Series P-25, No. 381.
United States Bureau of the Census. 1968. Marital Status and Family Status: March 1967. Current Population Reports, Series P-20, No. 170.
Whelpton, P. K., A. A. Campbell, and J. E. Patterson. 1966. Fertility and Family Planning in the United States. Princeton, N. J.: Princeton University Press.
About this article
Cite this article
Siegel, J.S., Akers, D.S. Some aspects of the use of birth expectations data from sample surveys for population projections. Demography 6, 101–115 (1969). https://doi.org/10.2307/2060384
- Family Size
- Total Fertility Rate
- Current Population Survey
- Population Projection
- Spacing Pattern