Volume 9 - Article 6 | Pages 111–118  

A diminishing population whose every cohort more than replaces itself

By Robert Schoen, Stefan H. Jonsson

Abstract

We observe that a dynamic population model can have period fertility that is always below replacement and cohort fertility that is always above replacement. We ask whether such a paradoxical population will get larger or smaller, and show that it must become smaller. Cohort replacement does not imply population replacement, and emphasizing fertility timing and cohort fertility ignores the issue of relative cohort size. The resolution of this apparent paradox reinforces the importance of the level of period fertility in demographic analysis.

Author's Affiliation

Other articles by the same author/authors in Demographic Research

Estimating multistate transition rates from population distributions
Volume 9 - Article 1

Analyzing hyperstable population models
Volume 49 - Article 37

A dynamic birth-death model via Intrinsic Linkage
Volume 28 - Article 35

Age-specific growth, reproductive values, and intrinsic r
Volume 24 - Article 33

The metastable birth trajectory
Volume 21 - Article 25

A behaviorally-based approach to measuring inequality
Volume 19 - Article 49

Changing mortality and average cohort life expectancy
Volume 13 - Article 5

Age-specific contributions to changes in the period and cohort life expectancy
Volume 13 - Article 3

Intrinsically dynamic population models
Volume 12 - Article 3

On the Impact of Spatial Momentum
Volume 6 - Article 3

Toward a General Model for Populations with Changing Rates
Volume 4 - Article 6

Most recent similar articles in Demographic Research

The big decline: Lowest-low fertility in Uruguay (2016–2021)
Volume 50 - Article 16    | Keywords: adolescent fertility, birth order, fertility, Latin America, ultra-low fertility, Uruguay

Cohort fertility of immigrants to Israel from the former Soviet Union
Volume 50 - Article 13    | Keywords: age at first birth, assimilation, cohort analysis, fertility, immigration, parity, religiosity

Fertility decline, changes in age structure, and the potential for demographic dividends: A global analysis
Volume 50 - Article 9    | Keywords: age structure, demographic dividend, demographic transition, fertility, migration, population momentum, working-age population

Analyzing hyperstable population models
Volume 49 - Article 37    | Keywords: birth trajectory, cohort analysis, cyclical populations, dynamic population model, fertility, hyperstable, period

Measuring the educational gradient of period fertility in 28 European countries: A new approach based on parity-specific fertility estimates
Volume 49 - Article 34    | Keywords: education, Europe, period fertility, quantum, tempo, total fertility rate (TFR)