HAS U.S. FERTILITY DECLINED? TRENDS BASED ON PERIOD VS. COHORT MEASURES OF FERTILITY.

In this paper, we show that the widely publicized decline in U.S. fertility is an artifact of tempo distortions that are known to affect trends based on the total fertility rate (TFR) when birth rates at different ages are trending rapidly. Our cohort-based analyses of trends, which are not subject to such distortions and which are estimated from the same natality data as official estimates of TFR, provide a picture of very gradual cohort change, with declines in births at earlier ages offset by increases at later ages. We conclude that fertility in the United States has remained, and is likely to remain, at or near replacement levels. [ABSTRACT FROM AUTHOR]