Population Projections

NAME OF ORGANISATION
Australian Bureau of Statistics (ABS)

OVERVIEW
Every two to three years the ABS publishes a new set of population projections. The new projections are produced in order to take advantage of the most recent information on components of population change and to take account of the latest estimates of the resident population and thereby service the needs of users with up-to-date population projections.

Ad hoc projections are produced on a consultancy basis where the client agrees to the assumptions and to meet the costs involved.

PURPOSE
To help the understanding of the implications on the population of specified assumptions. The projections are used to help address a large range of issues including those associated with retirement income, population, housing and parliamentary representation.

SCOPE
The scope of population projections includes all persons who are usual residents of Australia.

DATA DETAIL

Conceptual framework
There are many techniques which may be used for population projections, ranging from simple extrapolations through broad economic, social and time-series analysis to detailed component methods.

The ABS uses the cohort-component method which begins with a base population for each sex by single years of age and advances it year by year by applying assumptions regarding future mortality and migration. Assumed age-specific fertility rates are applied to the female population of child-bearing ages (15 to 49 years) to provide the new cohort of births. This procedure is repeated for each year in the projection period for each State and Territory and for Australia. The resulting population projections for each year for the States and Territories, by sex and single years of age, are adjusted to sum to the Australian results.

The projection results published by the ABS are not intended as predictions or forecasts, but are illustrations of growth and change in the population which would occur if the assumptions about future demographic trends prevail over the projection period. As such, it is the assumptions used which have the greatest baring on the final projected outcomes.

While the assumptions for the projections are formulated on the basis of an assessment of past demographic trends, both in Australia and overseas, and their likely future dynamics, there is no certainty that any of the assumptions will or will not be realised. In addition, no assessment has been made of changes in non-demographic conditions.

Accordingly, alternative projections are produced in recognition of this uncertainty and to provide users with a range of options. For example, the publication Population Projections, Australia 1999-2101 (Catalogue no. 3222.0) contains a series of projections based on differing combinations of two alternative assumptions of fertility, three alternative assumptions for net overseas migration and three alternative assumptions for interstate migration. Only one assumption was used for mortality. In addition, an assumption of no net overseas migration was also used.

For more information on constructing population projections see 3228.0 - Demographic Estimates and Projections: Concepts, Sources and Methods

Main outputs
1. The projected total population of Part of State, States and Territories, and for Australia as a whole, by sex and either single years of age or five-year age grouping are produced for 30 June of each year of the projection period. In addition, sex ratios are available for each year of the projection period, as well as age by sex listings of the percentage distribution and the mean and median ages of the projected population. Various components of change (ie births, deaths, total natural increase, net overseas migration, net interstate migration, total net migration, total population increase and the number of infant deaths) are also available for each year of the projection.

2. A set of statistical local area, postal area and census collection district population projections is available which was produced as a statistical consultancy service. The projections are consistent with a specified published series and take account of the latest demographic trends and land use indicators available to the ABS. While the ABS takes responsibility for the method employed, the assumptions used are the responsibility of the client and the projections are not official ABS statistics.

3. For projections produced as consultancies, output is as specified by the client.

Classifications
The Australian Standard Geographical Classification (ASGC) is used.

Other concepts (summary)
n/a

GEOGRAPHIC DETAIL
Australia
New South Wales
Victoria
Queensland
South Australia
Western Australia
Tasmania
Northern Territory
ACT
Statistical Local Area
Census Collection District
Part of State Metropolitan
Part of State Extra-Metropolitan
CD Derived Postcode
Other (specify below)

Comments and/or Other Regions
Projections for other areas can be produced on request.

COLLECTION FREQUENCY
Other

Frequency comments
At National, State and Part of State (from 1998) levels - every 2-3 years.
Data provided in response to statistical consultancies at various geographical levels.

COLLECTION HISTORY
Interest in projections of the Australian population developed after World War II with the widening of the social policy agenda in government and community. The first substantial involvement by the Commonwealth Bureau of Census and Statistics [known since 1974 as the Australian Bureau of Statistics (ABS)] came in 1956 when a series of five yearly projections (1960 to 1975) were prepared for the Inter-departmental Committee set up to review the Retiring Age. This led to the publication by the Statistician (ABS) the next year of single year national projections series covering 1955 to 1975. In 1965 the ABS released the first issue "for general publication of a series of projections of the future population." The ABS continued to produce national projections during the 1960s. Various ABS State Offices, sometimes in cooperation with State Government agencies, had also begun producing population projections for their respective States.

In 1971 the ABS published for the first time a set of national, State and Territory projections under the one cover. As today, these projections used "an iterative mathematical process ... based on assumptions about future trends in mortality, fertility and net migration, derived from those of the recent past." During the 1970s, interest grew also in developing population projections at regional and local (sub-State) level. Various State governments and some university people took initiatives in that direction.

The ABS itself began producing local area projections on a consultancy basis in the early 1990s. This course was re-affirmed by the 1996 ABS Review of Demographic Statistics (see the ABS website, Demography Working Paper 96/2).

In 2001 the ABS published Statistical Local Area (SLA) projections for the first time. Projections were produced and published for SLAs in Tasmania and Northern Territory after agreement was reached between the ABS and the respective State/Territory governments.

Since 1978 the ABS has published population projections on a regular basis.

Base Year	Month/Year published	Time Period	Population projected	Catalogue number
1978	July 1979	1978-2011	National only	3204.0
1978	May 1979	1978-2011	National and States	3214.0
1981	November 1982	1981-2021	National only	3204.0
1981	May 1983	1981-2021	National and States	3214.0
1984	May 1985	1984-2021	National and States	3222.0
1987	September 1988	1987-2031	National and States	3222.0
1989	November 1990	1989-2031	National and States	3222.0
1993	May 1994	1993-2041	National and States	3222.0
1995	July 1996	1995-2051	National and States	3222.0
1997	July 1998	1997-2051	National, States and Parts of States	3222.0
1999	August 2000	1999-2101	National only	3222.0
1999	August 2000	1999-2051	National, States and Parts of States	3222.0
1999	July 2001	1999-2021	Statistical Local Areas, Northern Territory	3222.7
1999	October 2001	1999-2021	Statistical Local Areas, Tasmania	3222.6