COHORT ANALYSIS AND DEMOGRAPHIC TRANSLATION - A COMPARATIVE-STUDY OF RECENT TRENDS IN AGE SPECIFIC FERTILITY RATES FROM EUROPE AND NORTH-AMERICA

In this paper the author proposes an alternative formulation of Ryder’s equations of demographic translation by constructing a filter which relates period and cohort-based parametric fertility schedules. The resulting filter is used to study fertility data from eight countries in Europe and North America. The author concludes that although a cohort-based model can explain all but the short-run variations in period fertility, the resulting model would have to be quite complex. In particular, it would need to explain the observed tendency for changes in the tempo and spread of cohort fertility to lead changes in the quantum of cohort fertility by several years. An analysis of the spectral properties of the translation filter indicates that a period-based model could easily produce this pattern. The fact that the period-based model provides a more parsimonious description of the observed patterns sheds doubts on the predictive value of cohort-based models of fertility. © 1990 Taylor & Francis Group, LLC.