Demographic explanations for the recent rise in Europe's fertility

John Bongaarts, Population Council
Tomas Sobotka, Vienna Institute of Demography

Fertility as measured by the period total fertility rate increased in the large majority of European countries over the past decade. The present study first examines two perspectives on the demographic drivers of this largely unexpected trend: (1) the disappearance of period tempo effects that have distorted the total fertility rate downward in the past as the age at childbearing rose , and (2) a cohort driven process of recuperation at older ages of births that were postponed at younger ages. The empirical analysis is based on data from the Human Fertility Database with a focus on patterns and trends in the Czech Republic, the Netherlands and Sweden. This assessment concludes that the two perspectives are consistent with one another, but that period changes provide a more parsimonious explanation for recent trends. The paper’s second section examines the role of rising tempo distortions as the cause of low fertility in the 1990s and of their disappearance as the cause of the recent upturn. Two variants of the Bongaarts-Feeney method for removing these distortions are presented: (1) the conventional approach based on standard and widely available age-order specific fertility rates of the second order, and (2) an alternative life-table approach which makes tempo adjustments to order specific hazard rates. The latter method is preferred because it adjusts for the parity composition of the female population but its application has been limited in the past due to a lack of data. A substantial part of the recent upturn in fertility is found to be due to the disappearance of tempo distortions. The discussion highlights the analytic difficulties in interpreting quantum and tempo trends and attempts to reconcile differing interpretations of the demographic causes of recent fertility trends.