Census of Population and Housing - Counts of Aboriginal and Torres Strait Islander Australians methodology

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Reference period
2021

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This publication presents results from the 1971 to 2021 Census of Population and Housing (Census).

For the respective methodologies, refer to the following:

Data definitions

Table 1. Data definitions for Census of Population and Housing - Counts of Aboriginal and Torres Strait Islander Australians, 2021
MeasurementCollectionData itemsInclusions/exclusions
National count - Usual ResidenceCensus 1971-2021Indigenous status (INGP) Main Statistical Area Structure (Main ASGS) – Place of Usual ResidenceAll persons Denominator includes Other Territories
State/Territory of Usual ResidenceCensus 1971-2021Indigenous status (INGP) Main Statistical Area Structure (Main ASGS) – Place of Usual Residence Age in 5 year age groups (AGE5P)All persons Denominator includes Other Territories  
State/Territory of EnumerationCensus 2011-2021Indigenous status (INGP) Main Statistical Area Structure (Main ASGS) – Place of EnumerationAll persons Denominator includes Other Territories
Census counts by age and sexCensus 2011-2021Indigenous status (INGP) Main Statistical Area Structure (Main ASGS) – Place of Usual Residence (State/Territory only) Age in 5 year age groups (AGE5P)All persons Denominator includes migratory-offshore-shipping and no usual address  
Census counts, Local Government AreasCensus 2011-2021Indigenous status (INGP) Local Government Areas – Place of Usual ResidenceAll persons Denominator includes migratory-offshore-shipping and no usual address
Census counts, Indigenous StructureCensus 2011-2021Indigenous status (INGP) Indigenous Structure – Place of Usual ResidenceAll persons Denominator includes migratory-offshore-shipping and no usual address
Census counts, Greater Capital City Statistical AreasCensus 2011-2021Indigenous status (INGP) Greater Capital City Statistical Areas – Place of Usual ResidenceAll persons Denominator includes migratory-offshore-shipping and no usual address
Census counts, Remoteness AreasCensus 2011-2021Indigenous status (INGP) Remoteness Areas – Place of Usual Residence Age in 5 year age groups (AGE5P)All persons Denominator includes migratory-offshore-shipping and no usual address
Census counts, Empowered CommunitiesCensus 2021Indigenous status (INGP) Empowered Communities – Place of Usual Residence Age in 5 year age groups (AGE5P)All persons Denominator excludes areas not in any Empowered Community

Indigenous status

In Australia, the method for collecting information about Indigenous status is through self-identification. The ABS Standard Indigenous question is used in all ABS data collections. It is also used across a wide range of government agencies and Australian Aboriginal and Torres Strait Islander organisations. For more information, see the Indigenous Status Standard, 2014, Version 1.5.

Responses to the Indigenous status question are captured automatically from mark box responses on the form, so the risk of processing error is minimised. Where respondents identify as both Aboriginal and Torres Strait Islander, they are instructed to mark both the 'Yes, Aboriginal' and 'Yes, Torres Strait Islander' boxes. In cases where a respondent marked both ‘No’ and ‘Yes’ boxes, their Indigenous Status is set to ‘Not stated’.

Indigenous status data is available from the 1971 Census onwards. A question on origin has been asked in every Census. However, prior to the 1971 Census, Aboriginal and Torres Strait Islander peoples were counted in order to exclude them from population estimates for each state and territory.

The 1971 and 1976 censuses asked each person's racial origin. Since the 1981 Census the word 'racial' has been dropped from the question. The 1996 Census was the first Census to allow people's origins to be recorded as both Aboriginal and Torres Strait Islander, prior to this only one or the other could be recorded.

No changes have been made for 2021.

For more information, see the the 2021 Census Dictionary entry for Indigenous status (INGP).

Indigenous status not stated

In every census, there are people who do not complete a census form but are in a dwelling that was considered occupied on Census night. In such cases, ABS imputes people into these dwellings. Imputation is the process that attempts to fill in basic information for the people who didn’t respond to the Census. Currently, this information is limited to a person’s age, sex, usual residence and marital status, but Indigenous status is not imputed. 

For more information on Indigenous status not stated in the 2021 Census, see section 3.5 of the Report on the quality of 2021 Census data: Statistical Independent Assurance Panel to the Australian Statistician.

Intercensal change

Intercensal change is the change between two Census periods. It is used to describe increases and decreases in Census counts over time. Intercensal change is calculated using counts and is expressed as a percentage.

The forumla for intercensal change is:

\(\Large\frac{Census\space count\space A - Census\space count\space B}{Census\space count\space B} \times 100 \)

Where Census count A is the most recent time point.

There have been significant increases in the number of people identifying as having Aboriginal and/or Torres Strait Islander origin between Censuses that can impact intercensal change reporting.

Increases in the population are influenced by demographic factors such as births, deaths and migration, and by non-demographic factors including changes in whether or not a person identified as Aboriginal and/or Torres Strait Islander in each Census, the identification of children or others who have had their form completed by parents or someone else on their behalf, and the impact of communications and collection procedures. Changes in Indigenous status between Censuses can affect the interpretation of Census data for Aboriginal and Torres Strait Islander peoples. It is important to remember that Indigenous status is collected through self-identification and any change in how a person chooses to identify will affect the count of Aboriginal and Torres Strait Islander peoples in the Census. 

Sex ratio

Sex ratio is the number of males per 100 females.

The formula for sex ratios is:

 \(\LARGE\frac{Count\space of\space males}{Count\space of\space females}\space \times\space 100\)

Proportions

Proportions of persons by Indigenous status include 'not stated' responses in the denominator unless otherwise indicated. For example, the proportion of people in Australia who are of Aboriginal and/or Torres Strait Islander origin was calculated by dividing the number of persons identified as Aboriginal and/or Torres Strait Islander in origin by the total population and expressing the result as a percentage. The 'total population' includes records coded to 'not stated' unless otherwise indicated.

Torres Strait Region

Data for the Torres Strait Region in Tables 4.1 and 4.2 in ‘Queensland’ (see data downloads) includes:

  • all Indigenous Locations (ILOCs) in the Torres Strait Indigenous Region (IREG)
  • two ILOCs – Bamaga and surrounds and Seisia – from the Cape York IREG

These ILOCs were then filtered to only include the Statistical Area Level 1s (SA1s) that align with the Torres Strait Regional Authority, Regional Map.

The table below shows which SA1s and ILOCs were used to extract data for the Torres Strait Region.

Table 2. Indigenous Locations and Statistical Area Level 1s included in the Torres Strait Region(a)
2021 SA1 code2021 ILOC code2021 ILOC name2021 IREG code2021 IREG name
3150114010130700402Poruma (Coconut) Island307Torres Strait
3150114010230700302Kubin (Moa Island)307Torres Strait
3150114010330700202Dauan Island307Torres Strait
3150114010430700503Ugar (Stephens) Island307Torres Strait
3150114010530700105TRAWQ (Thursday Island)307Torres Strait
3150114010630700104Port Kennedy (Thursday Island)307Torres Strait
3150114010730700104Port Kennedy (Thursday Island)307Torres Strait
3150114010830700103Muralag and Inner Islands307Torres Strait
3150114010930700105TRAWQ (Thursday Island)307Torres Strait
3150114011030700103Muralag and Inner Islands307Torres Strait
3150114011430700104Port Kennedy (Thursday Island)307Torres Strait
3150114011530700102Horn Island307Torres Strait
3150114011630700104Port Kennedy (Thursday Island)307Torres Strait
3150114020130700401Iama (Yam) Island307Torres Strait
3150114020330700402Poruma (Coconut) Island307Torres Strait
3150114020430700501Erub (Darnley) Island307Torres Strait
3150114020530700502Mer (Murray) Island307Torres Strait
3150114020630700201Boigu Island307Torres Strait
3150114020730700202Dauan Island307Torres Strait
3150114020830700101Hammond Island307Torres Strait
3150114020930700503Ugar (Stephens) Island307Torres Strait
3150114021030700203Saibai Island307Torres Strait
3150114021230700303Mabuiag Island307Torres Strait
3150114021330700302Kubin (Moa Island)307Torres Strait
3150114021430700304St Pauls (Moa Island)307Torres Strait
3150114021530700403Warraber Island307Torres Strait
3150114021630700404Masig (Yorke Island)307Torres Strait
3150114021730700301Badu Island307Torres Strait
31501139903 3150114011130300801Bamaga and Surroundsᵇ303Cape York
3150113990530300804Seisia303Cape York
a. No correspondence was required for 2016 and 2011 data as there were no significant boundary changes impacting the Torres Strait Region in the ASGS in either year. All information in the table above uses 2021-2026 Indigenous Structure codes and names. b. There are two SA1s that cover the Bamaga and Surrounds ILOC. Both SA1s have been included in data for the Torres Strait Region for completeness.

About ABS Geography

The Australian Statistical Geography Standard (ASGS) provides a framework of statistical areas used by the Australian Bureau of Statistics (ABS) and other organisations to enable the publication of statistics that are comparable and spatially integrated. The ASGS provides users with a set of standard areas that can be used for analysing, visualising and integrating statistics produced by the ABS and other organisations. See the ASGS for further information.

The tables in this publication are presented by the following ASGS ABS Structures:

Main Structure

  • State and Territory

Indigenous Structure

  • Indigenous Regions (IREG), Indigenous Areas (IARE) and Indigenous Locations (ILOC)

Local Government Areas

  • State and Territory

Greater Capital City Statistical Areas

  • State and Territory

Remoteness Areas

  • State and Territory

Further information about ABS statistical geography and a diagram of how the various ABS Structures interrelate can be found in the ASGS.

The Indigenous Structure is based on the Aboriginal and Torres Strait Islander peoples’ population distribution in the broader Australian community, so is ideal for analysis of Aboriginal and Torres Strait Islander data. In the ASGS Indigenous Structure, Indigenous Locations (ILOCs) are the smallest available unit. These are combined to create Indigenous Areas (IAREs) and then Indigenous Regions (IREGs). See the ASGS Indigenous Structure for further information.

The Remoteness structure is derived from the Accessibility/Remoteness Index of Australia Plus (ARIA+) produced by the Hugo Centre for Population and Migration Studies at the University of Adelaide. The base geography used to construct the five Remoteness Areas in the 2021 Census was different between 2011 and 2016; however, the impact of the change in classification is minimal. In most cases it is possible to make a comparison of the same Remoteness Area across two Censuses. For more information about the classification refer to Remoteness Structure | Australian Bureau of Statistics (abs.gov.au). For further information about the changes in Remoteness Areas between 2016 and 2021 refer to Remoteness Areas | Australian Bureau of Statistics (abs.gov.au).

This publication also includes tables for Empowered Communities Regions. The Empowered Communities Regions are unique to Empowered Communities and are not part of the ASGS. Further information about Empowered Communities is available on their website: Empowered Communities.

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