Age-period-cohort analysis of U.S. fertility: a realistic approach

A key question for the explanation of fertility trends in advanced societies is whether, in addition to age, period- rather than cohort-related factors matter. In this paper, we analyze a standard set of age-specific fertility rates – from the Human Fertility Database – on the United States between 1933 and 2015. More specifically, we describe and apply an Age-Period-Cohort (APC) modeling approach that relies on second differences as identifiable parameters. Results of our APC analyses tend to be consistent with an interpretation that gives a greater weight to period effects over shorter time horizons, with a significant pres-ence of smooth cohort effects over the longer term.