Consistent Projection of Fertility for Subnational Areas Using a Logistic Curve

Thomas M. McDevitt, U.S. Census Bureau

Ensuring consistency in assumed future fertility between subnational and national populations is one of the challenges involved in making subnational projections, particularly for countries with continuing fertility decline and for countries subject to reversals in fertility decline. This paper discusses the use of linear and logistic extrapolation of total fertility rates (TFRs), and the use of two methods based on the logistic, for ensuring consistency in assumed fertility across subnational areas and between subnational and national projected fertility. Reported and projected TFRs are used to assess the relative goodness of fit of projected TFR using alternative fertility projection models for subnational areas in twenty-one countries with three or more Demographic and Health Surveys.