Is US Fertility now Below Replacement? Evidence from Period vs. Cohort Trends
Level 3 - non-randomized controlled study
Graded by design analogy; demographic analysis of longitudinal birth cohorts and period trends.
OpenAlex W4386121133 · doi:10.1007/s11113-023-09821-y
What was done
The authors compared period and cohort approaches to evaluate whether US fertility has fallen below the replacement level of 2.10 births per woman. They evaluated period trends in total fertility rate (TFR) from 2007 to 2022 alongside observed and projected cohort cumulative fertility rates (CFR) at age 45 for US women born between 1959 and 2010.
What was found
Period TFR fell from 2.12 in 2007 to 1.67 in 2022. In contrast, older birth cohorts (born 1959–1987, aged 33 or older in 2020) had observed or projected CFRs at age 45 ranging between 2.00 and 2.24 births per woman. For younger cohorts (born 1988–2010, aged 10–32 in 2020), projected CFR at age 45 dropped below 2.00 due to reduced childbearing at younger ages.
Why it matters
Period TFR can exaggerate fertility declines due to the postponement of childbearing. Whether US lifetime fertility truly falls below replacement depends on whether younger cohorts offset early-age fertility drops with higher fertility at older ages.
Limits
The abstract does not state the primary data sources or exact sample sizes. Findings for younger cohorts (born 1988–2010) rely heavily on projections of future age-specific fertility rates, which remain uncertain.
Cited by
- supports According to the CDC and Pew Research, the US total fertility rate reached an all-time recorded low of 1.6.