There are a number of issues which impact on the use of Census data for measuring the size of the Indigenous population. These include: under enumeration of the Indigenous population, interpretation of Census records where Indigenous status is unknown, and the changing level of reported identification as an Aboriginal and/or Torres Strait Islander person.
The estimated resident population (ERP) is the official measure of the population of Australia and the states and territories and is adjusted for net undercount and unknown Indigenous status. In addition to estimated resident population for the total population, the ABS produces estimated resident population by Indigenous status with the following categories:
- Aboriginal origin only
- Torres Strait Islander origin only
- both Aboriginal and Torres Strait Islander origin
To arrive at the estimated resident population for the Aboriginal and Torres Strait Islander population, the Census count (on a usual residence basis) is adjusted for instances in which Indigenous status is unknown and for net undercount. For the purposes of population estimates, Census records with unknown Indigenous status are allocated as either Indigenous or non-Indigenous according to the distribution of stated responses within each age group, sex, Census form type and geographic area. For more information on the ERP see Population Distribution, Aboriginal and Torres Strait Islander Australians
(cat. no. 4705.0) and the Indigenous estimated resident population - method of calculation
feature article in Australian Demographic Statistics, March quarter 2007
(cat. no. 3101.0).
The preliminary Indigenous estimated resident population for 30 June 2006 (517,174) is 14% higher than the 2006 unadjusted Census count (455,026), and primarily reflects adjustments for net undercount and unknown Indigenous status. Final resident population estimates by Indigenous status will be available in August 2008 and released in a datacube spreadsheet (cat. no. 3238.0.55.001) on the ABS web site.
ERP should be used when discussing the size and structure of the Indigenous population and has been used in Chapter 2: Population distribution and structure. ERP is not available at fine levels of geography and in these cases Census counts can be used. Census counts provide information on population characteristics for all geographic areas and population groups and are used in the population characteristics chapters in this report.
There are two types of Census counts available:
- Census counts based on where people are when counted (place of enumeration)
- Census counts based on where people usually live (place of usual residence).
Usual residence counts are generally used for geographical analysis as they include persons away from home at the time of Census and exclude temporary visitors for any given location. Nationally, 30,853 Indigenous people (7%) were identified and counted at a location other than their usual address at the time of the 2006 Census. Unless otherwise stated, place of usual residence counts are used in the population characteristics chapters in this report.