“The growth of Australia’s very elderly population: past estimates and probabilistic forecasts” and “Visualising the demographic factors which shape population age structure”

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Presenter:  Dr Tom Wilson

Date: Oct 12, 2016

Time: 11:00am to 12:30pm

Contact person:  The LEBA Research and Postgraduate Office
T: 08 8946 6156
E: LEBAResearch@cdu.edu.au

Location:  Lecture theatre Blue 5.1.01

Abstract – Topic 1: “The growth of Australia’s very elderly population: past estimates and probabilistic forecasts”
Official population estimates in Australia are overstated at the very highest ages, resulting in inaccurate mortality rates, and unreliable forecasts. Official population forecasts are not accompanied by information about their uncertainty, and do not extend into the centenarian ages. The aim of this paper is to present more accurate estimates of the very elderly population of Australia (those aged 85+) from 1971 to 2014, and probabilistic forecasts out to 2051 by sex and single years of age up to age 110+. Population estimates were calculated from death counts using Extinct Cohort and Survivor Ratio methods, the latter being a newly-refined version. Population forecasts were produced using a probabilistic cohort-component model. The 85+ population of Australia grew from 69,000 in 1971 to 456,000 in 2014, in large part due to mortality reductions. It is forecast to increase to 1.90 million by 2051, with the 95% prediction interval spanning 1.51 to 2.37 million. The future growth in centenarians is proportionally far greater, but relatively more uncertain. Although the extent of future growth cannot be forecast precisely, huge increases in Australia’s very elderly population will eventuate.

AbstractTopic 2: “Visualising the demographic factors which shape population age structure”
The population pyramid is one of the most popular tools for visualising population age structure. However, it is difficult to discern from the diagram the relative effects of different demographic components on the size of age-specific populations, making it hard to understand exactly how a population’s age structure is formed. The aim of this paper is to introduce a type of population pyramid which shows how births, deaths, and migration have shaped a population’s age structure. Births, deaths, and population data were obtained from the Human Mortality Database and the Australian Bureau of Statistics. A variation on the conventional population pyramid, termed here a components-of-change pyramid, was created. Based on cohort population accounts, it illustrates how births, deaths, and net migration have created the population of each age group. A simple measure which summarises the impact of net migration on age structure is also suggested. Example components-of-change pyramids for several countries and subnational regions are presented, which illustrate how births, deaths, and net migration have fashioned current population age structures. The influence of migration is shown to vary greatly between populations. The new type of pyramid aids interpretation of a population’s age structure and helps to understand its demographic history over the last century.

Tom is an applied demographer specialising in population and household projections, migration analysis, the indirect estimation of demographic data, Indigenous demography, very elderly demographic trends, migration analysis and subnational demographic change. His current projects include ‘Improved Indigenous population projections for policy and planning’ (ARC Linkage Project), ‘Improving subnational population projections’ (ARC Discovery Project), and ‘Reconciling migration flows and stocks to study ethnic population changes in Australia’ (ARC Discovery Project). He is the editor of the book Demography for Planning and Policy: Australian Case Studies, recently published by Springer.

RSVP by Monday 5pm 10th Oct 2016 via Outlook or email LEBAResearch@cdu.edu.au
Lunch will be provided upon receipt of an RSVP

**Waterfront Campus, Alice Springs, Adelaide, Melbourne & Sydney based colleagues interested in attending please request video conference in your RSVP (ITMS ask that requests are submitted at least 2 days prior)