Life tables methodology

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Reference period

2017 - 2019

Released

4/11/2020

Explanatory notes

Life tables

1 Internationally, life tables are used to measure mortality. In its simplest form, a life table is generated from age-specific death rates and the resulting values are used to measure mortality, survivorship and life expectancy. The life table depicts the mortality experience of a hypothetical group of newborn babies throughout their entire lifetime. It is based on the assumption that this group is subject to the age-specific mortality rates of the reference period. Typically this hypothetical group is 100,000 persons in size. For more information, see Demographic Methods and Concepts (Rowland, 2003).

2 Life tables in this release are current, or period, life tables, based on death rates for a short period of time during which mortality has remained much the same. Mortality rates used in the Australian and state and territory life tables are based on the occurrence of deaths in the 2017-2019 period and the estimated resident population at the mid-point of that period. The life tables do not take into account future assumed improvements in mortality.

3 Life tables may be complete or abridged, depending on the age interval used in the compilation. Life tables in these spreadsheets are complete life tables—they contain data by single years of age. Abridged life tables contain data for five-year age groups.

4 Life tables for males and females are released for Australia and states/territories. However, only the life expectancy at birth estimates for males, females and persons are released for the Statistical Area level 4 (SA4).

5 To construct a life table, data on population, deaths and births is needed. Mortality rates are smoothed to avoid fluctuations in the data. The mortality rate (qx), is the main function of the life table, all other functions are derived from it. The life tables presented in this release contain four columns of interrelated information. These functions are:

lx - the number of persons surviving to exact age x;
qx - the proportion of persons dying between exact age x and exact age x+1. It is the mortality rate, from which other functions of the life table are derived;
Lx - the number of person years lived within the age interval x to x+1; and
ex - life expectancy at exact age x.

Life tables based on assumed improvements in mortality

6 Life tables based on assumed improvements in mortality are produced by the ABS using assumptions on future life expectancy at birth, based on recent trends in life expectancy. These are not the ABS' official life tables and are only used as inputs to ABS population projections. For further information see Population Projections, Australia.

Australian life tables

7 The 2017-2019 national and state/territory life tables have been compiled using the final rebased ERP based on the 2016 Census data.

8 With the release of the 2010-2012 life tables, a small refinement was made to the method to bring Australia's mortality rates (qx values) into line with other comparable countries. The impact of these changes in life expectancy at birth estimates is minimal, though caution should be applied when interpreting changes to life tables over time. For more information, see:

State and territory life tables

9 Life tables for the states and territories are produced on the same principles as the Australian life tables with the exception of the crude death rate, m(x). Crude death rates are smoothed using the Australian life table through the application of the Hodrick-Prescott filter (Hodrick and Prescott, 1977). This overcomes problems associated with excessive noise in the single year of age rates. In addition, some minor smoothing and suppression of outliers is often required to achieve reasonable mortality curves with satisfactory goodness-of-fit statistics.

10 State and territory life tables produced by the ABS are available for:

1994-1996 to 1999-2001: published in the Demography set of releases (cat. no. 3311.1-3311.8)
2000-2002: available on request
2001-2003 to 2008-2010: published in Life Tables (cat. no. 3302.1.55.001-3302.8.55.001)
2009-2011 onwards: published in Life tables, States, Territories and Australia.

Statistical Area Level 4 life tables

11 Life expectancy at birth estimates for Statistical Area Level 4s are released for males, females and persons. They have been calculated with reference to state and territory life tables, using the Brass' Logit System (Brass, 1975). These small area life tables are based on age-specific death rates for each area, some of which may be zero where no deaths are recorded at these ages. The Brass' Logit technique enables the calculation of smooth abridged life tables for regions which have deficient age-specific death rates, by adjusting them with reference to a standard life table. The technique does not alter the overall level of mortality, but the age-specific functions of the life table are smoothed.

12 The Brass' Logit technique essentially compares mortality between the regional and standard life tables across ages, then a line of best fit is calculated to describe that relationship by age. The line of best fit is then used in conjunction with the standard life table to determine death rates for the small area life table. For a more detailed description of the Brass' Logit System, see Methods for Estimating Fertility and Mortality from Limited and Defective data (Brass, 1975).

Aboriginal and Torres Strait Islander Australian life tables

13 Life tables for the Aboriginal and Torres Strait Islander population were published in November 2018 in Life Tables for Aboriginal and Torres Strait Islander Australians, 2015-2017.

14 Estimates of life expectancy at birth for the total population released in Life Tables, States, Territories and Australia (cat. no. 3302.0.55.001) are constructed differently to estimates presented in Life Tables for Aboriginal and Torres Strait Islander Australians, 2015-2017. Estimates of life expectancy at birth for the Aboriginal and Torres Strait Islander population are derived from abridged life tables with an upper age limit of 85 years and over, using numbers of deaths registered in 2015-2017 and the population as at 30 June 2016. Estimates of life expectancy for the total population are based on complete life tables with an upper age group of 120 years and over, using deaths according to month of occurrence in 2015-2017 and quarterly population estimates. In addition, smoothing processes applied to both sets of life tables differ.

Acknowledgements

15 The ABS' releases draw extensively on information provided freely by individuals, businesses, governments and other organisations. The efforts of each state and territory's Registries of Births, Deaths and Marriages to improve the data quality, coverage and timeliness of death registration information, processes and systems are noted and valued by the ABS. Their continued cooperation is very much appreciated. Information received by the ABS is treated in strict confidence as required by the Census and Statistics Act 1905.

Related products

16 Other ABS products which may be of interest to users include:

17 ABS products and releases are available free of charge from the ABS website http://www.abs.gov.au. Click on Statistics to gain access to the full range of ABS statistical and reference information.

Additional statistics available

18 More detailed life table information can be obtained from data cubes (in Microsoft Excel format) available electronically, from the Downloads section of this release.

Data cubes

Table 1: Life tables, States, Territories and Australia, 2017-2019
Table 2: Life tables, Statistical Area Level 4, 2010-2012 to 2017-2019

Historical Population

Life expectancy

Privacy

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Inquiries

20 For further information about these and related statistics, contact the National Information and Referral Service on 1300 135 070.

21 The ABS also issues a daily Release Advice on the website which details the products to be released in the week ahead.

Bibliography

Australian Bureau of Statistics, Australian Statistical Geography Standard (ASGS): Volume 1 - Main Structure and Greater Capital City Statistical Areas, cat. no. 1270.0.55.001, ABS, Canberra.

Brass, W 1975, Methods for Estimating Fertility and Mortality from Limited and Defective Data, University of North Carolina at Chapel Hill, Chapel Hill.

Hodrick, Robert; Prescott, Edward C. (1977), Postwar U.S. Business Cycles : An Empirical Investigation, Journey of Money, Credit, and Banking, 20 (1) : 1-16.

Rowland, D. 2003, Demographic Methods and Concepts, Oxford University Press, New York.

Glossary

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Aboriginal and Torres Strait Islander death

The ABS Death Registrations collection identifies a death as Aboriginal and Torres Strait Islander where the deceased is recorded as Aboriginal, Torres Strait Islander, or both on the Death Registration Form (DRF). The Indigenous status is also derived from the Medical Certificate of Cause of Death (MCCD) for South Australia, Western Australia, Tasmania, the Northern Territory and the Australian Capital Territory from 2007. For 2015 data, the Queensland Registry of Births, Deaths and Marriages also used MCCD information for the first time to derive Indigenous status. This resulted in a noticeable decrease in the number of deaths for which the Indigenous status was 'not stated' and an increase in the number of deaths identified as Aboriginal and Torres Strait Islander in Queensland. For New South Wales and Victoria, the Indigenous status of the deceased is derived from the DRF only. If the Indigenous status reported in the DRF does not agree with that in the MCCD, an identification from either source that the deceased was an Aboriginal and/or Torres Strait Islander is given preference over non-Indigenous.

Age-specific death rate (ASDR)

The age-specific death rate (ASDR) is the number of deaths (registered) during the calendar year, at a specified age, per 1,000 of the estimated resident population of the same age at the mid-point of the year (30 June). Pro rata adjustment is made in respect of deaths for which the age of the deceased is not given.

Australian Statistical Geography Standard (ASGS)

The ASGS defines all the regions for which the ABS releases statistics within the one framework and is used by the ABS for the collection and dissemination of geographically classified statistics from 1 July 2016. It is the current framework for understanding and interpreting the geographical context of statistics released by the ABS.

For more information, please refer to Australian Statistical Geography Standard (ASGS): Volume 1 - Main Structure and Greater Capital City Statistical Areas (cat. no. 1270.0.55.001).

Birth

The delivery of a child, irrespective of the duration of pregnancy, who, after being born, breathes or shows any evidence of life such as a heartbeat.

Crude death rate (CDR)

The crude death rate in this release, is the number of deaths (occurred) during the calendar year per 1,000 estimated resident population at 30 June.

Death

Death is the permanent disappearance of all evidence of life after birth has taken place. The definition excludes all deaths prior to live birth. For the purposes of the ABS Death Registrations collection, a death refers to any death which occurs in, or en route to Australia and is registered with a state or territory Registry of Births, Deaths and Marriages.

Estimated resident population (ERP)

The official measure of the population of Australia is based on the concept of usual residence. It refers to all people, regardless of nationality, citizenship or legal status, who usually live in Australia, with the exception of foreign diplomatic personnel and their families. It includes usual residents who are overseas for less than 12 months over a 16 month period. It excludes overseas visitors who are in Australia for less than 12 months over a 16 month period.

Life expectancy

Life expectancy refers to the average number of additional years a person of a given age and sex might expect to live if the age-specific death rates of the given period continued throughout his/her lifetime.

Life table

A life table is a tabular, numerical representation of mortality and survivorship of a cohort of births at each age of life. The conventional life table is based on the assumption that as the cohort passes through life it experiences mortality at each age in accordance with a predetermined pattern of mortality rates which do not change from year to year. The life table thus constitutes a hypothetical model of mortality, and even though it is usually based upon death rates from a real population during a particular period of time, it does not describe the real mortality which characterises a cohort as it ages.

Due to differences in mortality patterns between males and females at different ages, life tables are generally constructed separately for each sex.

Life table functions

The mortality rate (qx), is the main function of the life table, all other functions are derived from it. The life tables presented in this release contain four columns of interrelated information. These functions are:

lx - the number of persons surviving to exact age x;
qx - the proportion of persons dying between exact age x and exact age x+1. It is the mortality rate, from which other functions of the life table are derived;
Lx - the number of person years lived within the age interval x to x+1; and
ex - life expectancy at exact age x.

Live birth

See Birth.

Mortality

See Death.

Statistical Area Level 4 (SA4)

An area defined in the Australian Statistical Geography Standard and designed for the output of labour force data and to reflect labour markets. In rural areas, SA4s generally represent aggregations of multiple small labour markets with socioeconomic connections or similar industry characteristics. Large regional city labour markets are generally defined by a single SA4. Within major metropolitan labour markets SA4s represent sub-labour markets. SA4s are built from whole SA3s. They generally have a population over 100,000 people to enable accurate labour force survey data to be generated. There are 107 SA4s and they cover the whole of Australia without gaps or overlaps.

For more information, please refer to Australian Statistical Geography Standard (ASGS): Volume 1 - Main Structure and Greater Capital City Statistical Areas (cat. no. 1270.0.55.001).

Year of occurrence

The year the death occurred.

APA

Citation

Life tables methodology

APA

Citation

Explanatory notes

Life tables

Life tables based on assumed improvements in mortality

Australian life tables

State and territory life tables

Statistical Area Level 4 life tables

Aboriginal and Torres Strait Islander Australian life tables

Acknowledgements

Related products

Additional statistics available

Privacy

Inquiries

Bibliography

Glossary

Show all

Aboriginal and Torres Strait Islander death

Age-specific death rate (ASDR)

Australian Statistical Geography Standard (ASGS)

Birth

Crude death rate (CDR)

Death

Estimated resident population (ERP)

Life expectancy

Life table

Life table functions

Live birth

Mortality

Statistical Area Level 4 (SA4)

Year of occurrence

Abbreviations

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