Tools for Making Assumptions for Cohort-Component Projection

Thomas M. McDevitt, U.S. Census Bureau

The U.S. Census Bureau’s Subnational Projections Toolkit includes workbooks for preparing base populations, fertility, mortality, and migration for subareas. Preparing consistent base-year population structures. The CTBL32 workbook also may be used to rake smaller area, independently derived base population age-sex structures to a control population age-sex structure prior to cohort-component projection. Projecting fertility and mortality. Workbooks PROJTFR and PROJe0 are designed to help ensure internal consistency of national and subnational projections of fertility (TFR) and mortality (e(0)). These workbooks enable the analyst to calculate projected TFR and e(0) for each subarea population as inputs to cohort-component projection. Projecting migration. The Toolkit’s MIGSUB workbook estimates area-specific in-migration, out-migration, and net migration for subnational areas. The pattern of internal migration from the reference census is used, along with user-provided assumptions about trend in migration levels, to project numbers of internal and international migrants for a user-specified time horizon.