Probabilistic population projections for countries with generalized HIV/AIDS epidemics

Abstract

In 2015, the United Nations (UN) issued probabilistic population projections for all countries up to 2100, by simulating future levels of total fertility and life expectancy and combining the results using a standard cohort component projection method. For the 40 countries with generalized HIV/AIDS epidemics, the mortality projections used the Spectrum/Estimation and Projection Package (EPP) model, a complex, multistate model designed for short-term projections of policy-relevant quantities for the epidemic. We propose a simpler approach that is more compatible with existing UN projection methods for other countries. Changes in life expectancy are projected probabilistically using a simple time series regression and then converted to age- and sex-specific mortality rates using model life tables designed for countries with HIV/AIDS epidemics. These are then input to the cohort component method, as for other countries. The method performed well in an out-of-sample cross-validation experiment. It gives similar short-run projections to Spectrum/EPP, while being simpler and avoiding multistate modelling.

Keywords:

• Bayesian hierarchical model
• cohort component projection method
• Estimation and Projection Package
• Spectrum
• UNAIDS
• World Population Prospects

Notes

1 Please direct all correspondence to David J. Sharrow, Center for Statistics and the Social Sciences, University of Washington, Seattle, WA 98195–4320, USA; or by E-mail: [email protected]

2 This work was supported by the Eunice Kennedy Shriver National Institute of Child Health and Human Development under Grant K01HD057246, Grant R01HD054511, and Grant R01HD070936.