EXPLANATORY NOTES

INTRODUCTION

1 This publication presents counts from the 2011 Census of Population and Housing for people who both identified as being of Aboriginal and Torres Strait Islander origin and were counted in the Census.

2 The 2011 Census of Population and Housing was held on 9 August 2011. The objective of the Census is to accurately measure the number and key characteristics of people in Australia and the dwellings in which they live, on Census Night. This provides a reliable basis for the estimation of the population of each of the states, territories and local government areas primarily for electoral purposes and the distribution of government funds. It also provides information about the characteristics of the population and its housing within small geographic areas and for small population groups. Census data supports a range of planning, administration, policy development and evaluation activities of government and other data users.


INDIGENOUS STATUS

3 The question about Indigenous status on the Census form asks whether each person is of Aboriginal and/or Torres Strait Islander origin. 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. This question format has been repeated in subsequent Censuses, including the 2011 Census.

4 For more information on definitional changes and Census questions, refer to the Census Dictionary, 2011 (cat. no. 2901.0).


SCOPE AND COVERAGE

5 The 2011 Census of Population and Housing was held on 9 August 2011. Australia's first national Census was held in 1911 and since 1961 a Census has been taken every five years, the frequency specified in the Census and Statistics Act (1905). The objective of the Census is to count the number of people in Australia on Census Night, identifying their key characteristics and those of the dwellings in which they live. 6 Following changes to the Australian Constitution as a result of the 1967 Referendum, Aboriginal and Torres Strait Islander peoples were included in official estimates of the Australian population. As a consequence, from the 1976 Census onwards, the Australian Bureau of Statistics (ABS) has developed and improved strategies to count the Aboriginal and Torres Strait Islander population throughout Australia. 7 The Census aims to count every person who spent Census Night in Australia. This includes Australian residents in Antarctica and Other Territories – Jervis Bay, Cocos (Keeling) Islands and Christmas Island. The other Australian External Territories (Norfolk Island and minor islands such as Heard and McDonald Islands) are outside the scope of the Australian Census. The only people who are excluded from the Census are foreign diplomats and their families.

8 The Census includes people on vessels in or between Australian ports as well as people on board long distance trains, buses or aircraft. Also included are those people outside Australia who are not required to undertake migration formalities, such as those on oil and gas rigs or on Australian Antarctic bases. People entering Australia before midnight on Census Night are counted, while people leaving an Australian port for an overseas destination before midnight on Census Night are not. Visitors to Australia are included regardless of how long they have been in the country or how long they plan to stay. However, for people who intend to be in Australia for less than 12 months, only basic demographic data are available. The Census includes homeless people and people camping out.

9 All occupied dwellings are counted in the Census with the exception of diplomatic dwellings. Unoccupied private dwellings are also counted, with the exception of unoccupied dwellings in caravan parks, marinas and manufactured home estates (self-contained dwellings that are built off-site and then transported to the estate for installation). Unoccupied residences of owners, managers or caretakers of such establishments are counted.


ENUMERATION PROCEDURES

10 In order to achieve the most accurate count of Aboriginal and Torres Strait Islander peoples in the Census, the ABS developed an Indigenous Enumeration Strategy. This Strategy was first introduced in the 1976 Census for remote areas of WA and NT, and has been expanded and improved for subsequent Censuses. This strategy aims to be culturally appropriate and to raise the quality of the Census counts for this population group.

11 The 2011 Census Indigenous Enumeration Strategy incorporated improvements to enumeration of Aboriginal and Torres Strait Islander people living in urban areas, as well as those living in remote Aboriginal and Torres Strait Islander communities. At a broad level, the improvements for the 2011 Census included:

• earlier and ongoing engagement
• a reduction in the overall enumeration period for Aboriginal and Torres Strait Islander communities
• an increase in the number of field staff recruited
• a greater level of support to Aboriginal and Torres Strait Islander people requiring assistance in completing their form, in both urban and remote areas.

12 In the majority of discrete Aboriginal and Torres Strait Islander communities, an interview approach was used, with local people employed and trained to conduct the interviews.

13 In pre-identified urban areas increased support and assistance were provided to Aboriginal and Torres Strait Islander people, including the option of collecting Census information through an interview.

14 For more information on the Indigenous Enumeration Strategy refer to 2011 Census Fact sheet Enumeration Procedures for Aboriginal and Torres Strait Islander Peoples available on the ABS website.

LIMITATIONS OF CENSUS DATA

15 There are four principal sources of error in Census data: respondent error, processing error, partial response and undercount. Quality assurance processes in the Census program aim to reduce error as much as possible, and to provide a measure of the remaining error to data users, to allow them to use the data in an informed way.

16 The Census Dictionary, 2011 (cat. no. 2901.0) provides more information on managing Census data quality.


DATA PRESENTATIONS AND CONSIDERATIONS

17 The proportions of the population shown in the tables in this publication include 'not stated' responses in the denominator. For example, the proportion of people in Australia who are of Aboriginal and/or Torres Strait Islander origin is calculated by dividing the number of persons identified as Aboriginal and/or Torres Strait Islander origin by the total population, and expressing the result as a percentage. The 'total population' includes records coded to 'not stated'.

18 The Census counts presented in this publication are based on usual residence. For information on usual residence and place of enumeration refer to the Census Dictionary, 2011 (cat. no. 2901.0).

19 Under the Census and Statistics Act (1905) it is an offence to release any information collected under the Act that is likely to enable identification of any particular individual or organisation. Introduced random error is used to ensure that no data are released which could risk the identification of individuals in the statistics.

20 Care is taken in the specification of tables to minimise the risk of identifying individuals. In addition, a technique has been developed to randomly adjust cell values. Random adjustment of the data is considered to be the most satisfactory technique for avoiding the release of Census data that may identify individuals. When the technique is applied, all cells are adjusted to prevent any such data being exposed. These adjustments result in small introduced random errors. However, the information value of the table as a whole is not impaired. For more detail refer to introduced random error in the Census Dictionary, 2011 (cat. no. 2901.0).


POPULATION ESTIMATES

21 Estimated Resident Population (ERP) is the official measure of the population of Australia. It 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. It excludes overseas visitors who are in Australia for less than 12 months. In the compilation of the ERP, important adjustments are made to the Census count based on place of usual residence. For further information about ERP, see Census Dictionary, 2011 (cat. no. 2901.0).

22 The ABS is undertaking a program of work based on results of the 2011 Census of Population and Housing and the 2011 Census Post Enumeration Survey (PES) to compile and release estimates of the Aboriginal and Torres Strait Islander population at 30 June 2011. Preliminary estimates at 30 June 2011 are available in Australian Demographic Statistics (cat. no. 3101.0) from the March quarter 2012 issue (released on 27 September 2012) onwards. These preliminary estimates are published by five year age groups, sex and state/territory of usual residence. Further disaggregation will be available when the final estimates of the Aboriginal and Torres Strait Islander population at 30 June 2011 are published in Population Estimates, Aboriginal and Torres Strait Islander Australians, 2011 (cat. no. 3238.0.55.001), scheduled for release in August 2013.

23 For further information regarding this work program see Information Paper: Aboriginal and Torres Strait Islander Demographic Statistics Work Program and Release Plans, Apr 2012 (cat. no. 3238.0.55.003).


RELATED INFORMATION

24 Additional information on data quality in the 2011 Census is available on the ABS website and the Census portal. Specific information on non-response rates, and conceptual and data issues can also be found on the Census portal.

25 Further information on Aboriginal and Torres Strait Islander statistics from the 2011 Census will be included in forthcoming ABS publications.