Variable-r Projection

Vladimir Canudas-Romo , Australian National University

Population projections remain among the core demographic undertakings. The Cohort Component Method (CCM) is the established procedure that combines basic demographic components (survival, fertility, and migration) information to determine the future population. However, the three basic demographic components need first to be forecasted by age and sex to then be included in the CCM. Here we propose using an alternative measure as the primary forecasting component, namely the age-specific growth rates. For each cohort the trend over time and age of those age-specific growth rates (or variable-r) remain unchanged from birth to older ages (around age 70, varying from country to country). Thus, the future age-specific growth rates for those who are below age 70 and present at the baseline moment of projection, are already determined by their current age-specific growth rates. For the rest of the age-groups the complementary fertility and mortality forecasts can be included to obtain forecasts of the population at those ages.

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 Presented in Session 73. Innovations in Demographic Modelling and Projections