title: Bayesian Population Projections for the United Nations.
abstract: The United Nations regularly publishes projections of the populations of all the world's countries broken down by age and sex. These projections are the de facto standard and are widely used by international organizations, governments and researchers. Like almost all other population projections, they are produced using the standard deterministic cohort-component projection method and do not yield statements of uncertainty. We describe a Bayesian method for producing probabilistic population projections for most countries that the United Nations could use. It has at its core Bayesian hierarchical models for the total fertility rate and life expectancy at birth. We illustrate the method and show how it can be extended to address concerns about the UN's current assumptions about the long-term distribution of fertility. The method is implemented in the R packages bayesTFR, bayesLife, bayesPop and bayesDem.
authors.affiliation: Department of Statistics, Box 354322, University of Washington, Seattle, WA 98195-4322. raftery@uw.edu ; Web: www.stat.washington.edu/raftery .
authors.forename: Adrian E
authors.initials: AE
authors.lastname: Raftery
authors.affiliation: Department of Statistics and Applied Probability and Saw Swee Hock School of Public Health, National University of Singapore, Singapore 117546; alkema@nus.edu.sg .
authors.forename: Leontine
authors.initials: L
authors.lastname: Alkema
authors.affiliation: Population Estimates and Projections Section, United Nations Population Division, New York, NY 10017; gerland@un.org .
authors.forename: Patrick
authors.initials: P
authors.lastname: Gerland
keywords: Bayesian hierarchical model; Leslie matrix; cohort component projection method; double logistic function; life expectancy; total fertility rate