The Australian Census Longitudinal Dataset (ACLD) is a representative 5% panel sample of Census records, linked together using statistical techniques. A panel sample collects responses from the same people over multiple Censuses. This article uses longitudinal data from the 2011 Census panel in the three-wave ACLD to explore identification as an Aboriginal and/or Torres Strait Islander person over the 2011, 2016 and 2021 Censuses.
Further information about the ACLD can be found here.
This article looks at spatial and demographic information regarding people who ever identified as an Aboriginal and/or Torres Strait Islander person in the 2011-2016-2021 three-wave ACLD. This includes people who identified as an Aboriginal and/or Torres Strait Islander person:
The three-wave ACLD contains over 1.2 million records from the 2011 Census, linked with corresponding records from the 2016 Census and the 2021 Census. People who were included in the 2011 Census sample but whose 2016 and/or 2021 responses could not be linked are altogether excluded from our analysis, resulting in a total record count of 814,337.
The ACLD and the Census differ on the number and proportion of people identifying as Aboriginal and/or Torres Strait Islander people due to the use of weighting and the removal of missed records in the ACLD.
The 2011-2016-2021 three-wave ACLD started with a panel sample collected from the 2011 Census and linked these records between Censuses. The 2011 panel contained over 1.2 million records, with 76.0% (923,517) of these linked to 2016 records and 66.7% (814,337) linked to both 2016 and 2021 records.
Major causes for records failing to link between Census datasets include:
Records that were successfully linked from 2011 to 2016 and 2021 in the ACLD are weighted to a population benchmark. Weighting is done in order to scale the sample in accordance with the total Australian population. The benchmark used is based on the 2016 and 2021 Estimated Resident Population (ERP) and is adjusted by the estimated probability that a person belongs to the panel sample in the ACLD. This probability is created using the Address Five Years Ago question in the 2016 and 2021 Censuses. The weights for the 2011-2016-2021 three-wave ACLD range between 16.8 and 602.8.
Major sources of error in the ACLD include:
Further information regarding these sources of error can be found here.
The ACLD is a sample and, even when weighted to represent the wider population, it will not be the same as the full Census dataset. Users should always exercise caution when drawing comparisons between these two datasets.
There were 22,586 records belonging to people who had identified as an Aboriginal and/or Torres Strait Islander person in the 2011, 2016 or 2021 Censuses and were linked across all three Censuses.
The accuracy of results from Remote and Very Remote areas may be lower than other Remoteness Areas. Some dwellings do not have unique street addresses, and are instead listed by community name only. This makes it harder to link the relevant records across Censuses.
An individual who did not previously identify as an Aboriginal and/or Torres Strait Islander person, and who has identified in a later Census, will remain unidentified as an Aboriginal and/or Torres Strait Islander person in the earlier Census. Changes to a person's identification as an Aboriginal and/or Torres Strait Islander person may be subject to some sources of error. The method used to collect information on identification as an Aboriginal and/or Torres Strait Islander person in the ACLD varies in some Remote Areas, where tailored procedures, such as the Interviewer household form, may be used to complete the Census.
In the Census, status as an Aboriginal and/or Torres Strait Islander person is collected using the Standard Indigenous Question (SIQ). The SIQ has remained unchanged since it was first introduced in 1996. The Census is a self-response questionnaire and responses to the SIQ are either made by the person themselves or on their behalf by a trusted adult who is completing the questionnaire for the entire household.
There may be differences in how a person responds to the Standard Indigenous Question (SIQ) in one Census compared with another depending on whether Indigenous status is provided directly by the individual or by someone else on behalf of the household, or if there is a change in whether a person chooses to identify as being of Aboriginal and/or Torres Strait Islander origin in the Census. A person’s decision to identify as being of Aboriginal and/or Torres Strait Islander origin in the Census can be informed by many personal and external influences (historical and contemporary). For more detail, refer to ‘Changing identification in the Census and throughout life’ in Understanding change in counts of Aboriginal and Torres Strait Islander Australians: Census, 2021.
The Census does not collect information that could explain why a person may have identified in the each of the three Censuses or why their Indigenous status may change.