Assessing cohort birth expectations data from the Current Population Survey, 1971-1981.

Data from the fertility supplements to the Current Population Survey from 1971 to 1981 indicate that in the aggregate, the lifetime birth expectations of married women 18 to 39 years old in 1971 will closely approximate their completed cohort fertility. During this period, the youngest group of women, 18 to 24 years old, delayed their childbearing; their short-term expectations (1971-76) were not realized, but they made up enough births in the latter half of the decade to enable them to attain their lifetime birth expectations. In retrospect, the "failure" of birth expectations data to predict the "period" fertility downswing in the 1970s resulted not from poor predictions of married women, but rather from unanticipated marital and subsequent childbearing patterns of women who were single at the beginning of the decade. The authors conclude that birth expectations are useful predictors of completed cohort fertility, if adjustments are made to incorporate changes in the proportions married within the birth cohort.