Probabilistic population projections for countries with generalized HIV/AIDS epidemics

Probabilistic population forecasting: Short to very long-term

Population forecasts are used by governments and the private sector for planning, with horizons up to about three generations (around 2100) for different purposes. The traditional methods are deterministic using scenarios, but probabilistic forecasts are desired to get an idea of accuracy, assess changes, and make decisions involving risks. In a significant breakthrough, since 2015, the United Nations has issued probabilistic population forecasts for all countries using a Bayesian methodology that we review here. Assessment of the social cost of carbon relies on long-term forecasts of carbon emissions, which in turn depend on even longer-range population and economic forecasts, to 2300. We extend the UN method to very-long range population forecasts by combining the statistical approach with expert review and elicitation. While the world population is projected to grow for the rest of this century, it will likely stabilize in the 22nd century and decline in the 23rd century.

What have we learned about mortality patterns over the past 25 years?

In this paper, I examine progress in the field of mortality over the past 25 years. I argue that we have been most successful in taking advantage of an increasingly data-rich environment to improve aggregate mortality models and test pre-existing theories. Less progress has been made in relating our estimates of mortality risk at the individual level to broader mortality patterns at the population level while appropriately accounting for contextual differences and compositional change. Overall, I find that the field of mortality continues to be highly visible in demographic journals, including Population Studies. However much of what is published today in field journals could just as easily appear in neighbouring disciplinary journals, as disciplinary boundaries are shrinking.

Gender egalitarianism, perceived economic insecurity, and fertility intentions in Spain: A qualitative analysis

Economic uncertainty contributes to low fertility in many European countries. On the other hand, greater gender equality may positively influence fertility. This paper examines how these two forces interact in Spain. We use in-depth interviews to analyse fertility decision-making among young and highly educated partnered adults living in urban areas. Highly gender-egalitarian interviewees are less likely to perceive economic insecurity as an obstacle to proceeding to a next birth than less egalitarian interviewees. But there is not necessarily a difference in these two groups' overall fertility intentions, as highly egalitarian interviewees' greater valuation of stable employment for both partners requires institutional and policy support for dual-earner couples' childrearing. When we look only at interviewees who express economic insecurity, somewhat higher fertility intentions are expressed by those holding less gender-egalitarian attitudes. Our results underline the complexity of the interrelationships between economic insecurity, gender egalitarianism, and fertility intentions.

Bayesian projection of life expectancy accounting for the HIV/AIDS epidemic

Background

While probabilistic projection methods for projecting life expectancy exist, few account for covariates related to life expectancy. Generalized HIV/AIDS epidemics have a large, immediate negative impact on the life expectancy in a country, but this impact can be mitigated by widespread use of antiretroviral therapy (ART). Thus, projection methods for countries with generalized HIV/AIDS epidemics could be improved by accounting for HIV prevalence, the future course of the epidemic, and ART coverage.

Methods

We extend the current Bayesian probabilistic life expectancy projection methods of Raftery et al. (2013) to account for HIV prevalence and adult ART coverage in countries with generalized HIV/AIDS epidemics.

Results

We evaluate our method using out-of-sample validation. We find that the proposed method performs better than the method that does not account for HIV prevalence or ART coverage for projections of life expectancy in countries with a generalized epidemic, while projections for countries without an epidemic remain essentially unchanged.

Conclusions

In general, our projections show rapid recovery to pre-epidemic life expectancy levels in the presence of widespread ART coverage. After the initial life expectancy recovery, we project a steady rise in life expectancy until the end of the century.

Contribution

We develop a simple Bayesian hierarchical model for long-term projections of life expectancy while accounting for HIV/AIDS prevalence and coverage of ART. The method produces well-calibrated projections for countries with generalized HIV/AIDS epidemics up to 2100 while having limited data demands.