Bayesian Reconstruction of Two-Sex Populations by Age: Estimating Sex Ratios at Birth and Sex Ratios of Mortality

Mark C. Wheldon, Auckland University of Technology
Adrian Raftery, University of Washington
Samuel J. Clark, University of Washington
Patrick Gerland, United Nations Population Division

The original version of Bayesian reconstruction (Wheldon et al., 2013), a method for estimating age-specific fertility, mortality, migration and population counts of the recent past with uncertainty, produced estimates for female-only populations. Here we show how two-sex populations can be similarly reconstructed. This allows probabilistic estimation of sex ratios of births, mortality and population counts. We demonstrate the method by reconstructing the populations of India, Thailand, and Laos. Findings include: the posterior probability that some sex ratios at birth (SRBs) in India exceeded 1.06 are greater than 0.9, as is the probability that there was an increase in this parameter over the period of study. In both Thailand and Laos, we found strong evidence that life expectancy at birth (e0) was greater for females and, in Thailand, that the difference increased over the period of study. In India, the probability that female e0 was lower was 0.8.