The impact of changes in birth spacing on age at last birth

A response to Anderton

Datos Bibliográficos

ID11620394
AutoresPeter Mcdonald (0009-0004-5842-4444, Australian Institute of Family Studies), John Knodel (Population Studies Center, 1225 South University Avenue, Ann Arbor, Michigan 48104)
Año1989
Volumen26
Número3
Páginas471-472
Fecha de publicación1989-08-01
Peer ReviewedSí
Open AccessSí
TipoARTICLE
RevistaDemography (JOURNAL)
Identificadores de la revistaISSN: 0070-3370 • E-ISSN: 1533-7790
EditorialSpringer Science+Business Media (PUBLISHER • DE)
DOI10.2307/2061606
PMID2792482
OpenAlexW2092545343
IdiomaEN
Citas recibidas10

This article defends Knodels use of the age of mother at last birth and McDonalds decomposition exercise in the investigation of behavioral changes accompanying historical fertility declines and refutes criticisms of these indicators levied by Anderton. Anderton argued that 1) the use of the mothers age at last birth is sensitive to spacing and therefore is not a true measure of stopping behavior and 2) the use of McDonalds decomposition technique is inadequate to identify the role of spacing and is potentially misleading. Age at last birth is subject to a truncation effect insofar as a womens fertility history is ended by the onset of infecundity. Given the variability of age at onset of infecundity the variability in age at 1st birth and the variability in patterns of interbirth up to the nth birth the distance in time that the nth birth preceeds the onset of infecundity will also be variable. Assuming and evenly spaced distribution we can expect that the average gap between the nth birth and the onset of infecundity will be 1/2 of the average length of birth intervals around the onset of infecundity. Therefore if the intervals around the onset of infecundity increase age at 1st birth will drop by 1/2 the amount that the intervals increase. The last interbirth interval increased by only 4 months for the population under study and thus age at last birth could have been expected to drop by a maximum of 2 months as a result of changed spacing behavior. As the observed changes in age at last birth in the study populations were greater than 2 months there seems to be no challenge to the original conclusion confirming the importance and dominance of stopping behavior at the onset of fertility transition. As long as the onset of infecundity operates to truncate fertility the impact of a change in spacing patterns on age at last birth would need to be considered in the use of the McDonald equation. However this impact will be quite small generally and the equation is robust to this difficulty. In sum both indicators are useful for describing the broad outlines of changes in stopping and spacing behavior

Birth rate · Fertility · Population · Sociology · demographic modeling and climate adaptation · Demography · Family Dynamics and Relationships · Insurance, Mortality, Demography, Risk Management · Medicine