APPENDIX 2 POPULATION MEASURES
1 The ABS produces a number of Indigenous population estimates and counts used by stakeholders to develop policies and implement programs delivering services to Aboriginal and Torres Strait Islander people. The differences in each measure can be significant, largely due to differences in methodologies and timing. This appendix describes each of the population estimates and counts and highlights differences in their collection methodologies. Also included is an analysis of differences between 2001 CHINS and 2001 Census of Population and Housing population counts.
ESTIMATED RESIDENT INDIGENOUS POPULATION
2 The ABS produces estimated resident population data for Aboriginal and Torres Strait Islander people at a national, State or Territory and Statistical Local Area of usual residence level, disaggregated by age and sex. These are considered the best source of information about the size of Australia's Indigenous population. They are referred to as experimental, as the significant intercensal volatility in Indigenous census counts and the quality of data on births, deaths and migration of Indigenous persons do not support the standard approach to population estimation.
3 Estimated resident Indigenous populations for 1991 to 2001 were derived from 2001 census counts as described below:
4 For more information, see Experimental Estimates and Projections, Aboriginal and Torres Strait Islander Australians, 30 June 1991 to 30 June 2009 (cat. no. 3238.0).
- Firstly, various adjustments were applied to census counts of Indigenous persons by Statistical Local Area (SLA) of usual residence to produce the estimated population as at 7 August 2001 (that is, census night). These adjustments take account of factors such as non-response to the Aboriginal and Torres Strait Islander origin question in the census, unknown Indigenous status on census forms imputed by ABS when a form could not be obtained from persons identified in the field, net census undercount of Indigenous persons, and Australian residents temporarily overseas on census night.
- Secondly, the effects of births, deaths, overseas migration and interstate migration for the 38 days between 1 July and 7 August 2001 were removed to derive 30 June 2001 estimates.
- Thirdly, the 30 June 2001 estimates were 'survived' back to 30 June 1991 using life tables. This method is known as the reverse survival method. Zero net internal and overseas migration were assumed for this period.
CENSUS OF POPULATION AND HOUSING
5 The five yearly Census of Population and Housing is the most important source of a wide range of socioeconomic data on Aboriginal and Torres Strait Islander people. The Census aims to count every person in Australia.
6 Census data for nominated discrete Indigenous communities are collected by Census Field Officers (CFOs) and key representatives of the community, on a dwelling by dwelling, and person by person basis. CFOs physically visit each community and check all houses and temporary dwellings to gain the most precise and complete population count possible. People who are absent at the time of census and who are in a place where they cannot be found or counted (such as fishing or hunting) are recorded on the household form of their usual dwelling as if they were there. Otherwise, if they are in a place where they will be counted on another census form, they are included in the temporarily absent category. Also, at the end of the count, CFOs match census population counts with what the community thinks the population count should be and, if they do not match, discrepancies are assessed to determine if there have been any persons missed.
7 The Census provides counts of the Indigenous population by both place of enumeration (where the person was physically located on census night) and place of usual residence (where the person has lived or intends to live for a total of six months or more) for various geographical levels. Counts compiled on a usual residence basis are less likely to be influenced by seasonal factors, the effects of visitation and mobility issues, and events such as festivals, funerals, hunting or other cultural and sporting events.
8 Users should be aware that census data - for example, disaggregated by person characteristics such as labour force status and educational attainment - cannot be reconciled with estimated resident Indigenous population data, as they represent census counts which are not adjusted for underenumeration or other factors discussed above. Users should therefore exercise caution when using census characteristics data and estimated resident Indigenous population data together.
2006 COMMUNITY HOUSING AND INFRASTRUCTURE NEEDS SURVEY
9 In the 2006 CHINS, Indigenous population counts were collected for Aboriginal and Torres Strait Islander people living in discrete Indigenous communities for Australia, States and Territories and Remoteness Area. The CHINS population counts represent the reported usual population of Indigenous communities as stated by a community or Indigenous organisation key informant, not on a dwelling basis.
10 Two electronic questionnaires were utilised to collect CHINS data: a housing questionnaire; and a community questionnaire. CHINS data were collected during personal face-to-face interviews, conducted by trained ABS officers, with IHO and key community representatives.
11 IHO and community representatives were encouraged to refer to administrative records during the interview process to ensure as accurate information as possible. Refer to paragraphs 11 to 16 of the Explanatory Notes for more details on CHINS data collection.
12 Community population data were collected in both questionnaires from both the IHO and community representatives. Where the same person completed both forms, the population question was sequenced out of the electronic community form and the final derived CHINS population count was taken from the IHO reported count for the community.
13 Where the CHINS community questionnaire was not completed by the same person who completed the housing questionnaire, both population counts were assessed as part of the validation process. IHO and key community representatives' population counts were cross-matched. Where data were consistent (minor discrepancies were accepted), a final CHINS population count was derived using the count provided by the key community representative. Preference was given to the key community representative reported population as it was determined that the count was more likely to reflect the actual population that used the services and infrastructure of the community, particularly where the IHO representative had limited direct contact with the community and was located significant distances from the community.
14 Where discrepancies between the IHO and the key community representatives were large, further validation was undertaken involving follow-up contact with respondents to determine what the reported counts included.
15 In 2006, data were collected for a total 1,187 communities. A total of 990 community questionnaires (83%) were completed by the same person completing the housing questionnaire, of which 298 were main communities and 692 were outstations or homelands.
16 The CHINS population count asked key informants to distinguish between the usual resident population and the actual population serviced. However, in many instances the key informant was unable to provide that breakdown, which could have resulted in inflation of the actual population count. As well, many communities experienced a continual flow of visitors, so a continuous population count was often reported as this was the actual number of people using the communities' services and infrastructure. No adjustments are made to reported CHINS population counts to exclude persons that were not part of the usual reported population residing in the community.
17 CHINS population counts are also subject to double counting particularly when people move from one community/outstation to another community/outstation and stay significant periods in both. During the interview process, respondents were asked to avoid double counting and, as a result, highlighted outstations and homelands that were used on a temporary basis. Additional commentary was sought by interviewers for validation purposes to assist in explaining unoccupied localities, long term visitors and vacant dwellings which assisted respondents in reporting population counts. No attempt was made to amend CHINS population counts to reflect suspected double counting.
18 Additional discrepancies between CHINS and Census counts can be attributed to rounding. In CHINS, the key informant regularly rounds up (often to the nearest 50) the reported usual population. No adjustments are made to the CHINS population counts to account for this rounding.
TIMING OF CENSUS AND CHINS
19 Timing also contributes significantly to the differences between population counts obtained from the Census and CHINS. Mobility between communities, as well as between community and urban areas, can be high, particularly in the northern areas of Australia.
20 Data for CHINS are collected over a 4 month period between 1 March and 30 June in the same year as the Census. Census counts within Indigenous communities occur over a three week period around Census night in August. The impact of the changes in seasons (e.g. dry or wet season) over the period March to August on area inhabitation in some parts of Australia is significant, with no adjustments made between CHINS and Census population counts.
21 The table below illustrates the variation that occurred in 2001 between the CHINS key informant reported usual population count and the Census counts for selected community data for the Torres Strait Area. It also shows the estimated resident population for each area at 30 June 2001, derived in the way described in paragraph 3 of this Appendix.
Selected Discrete Indigenous Communities Population Measures - 2001
Estimated resident population(c)
|Torres Strait Area |
|Boigu Island |
|Saibai Island |
|Yorke Island |
|Mer Island |
|Iama Island |
|Darnley Island |
|Warraber Island |
|St Pauls |
|Horn Island |
|Dauan Island |
|Kubin (Moa Island) |
|Mabuiag Island |
|Stephens Island |
|(a) Place of usual residence. |
|(b) Source: Population Distribution, Aboriginal and Torres Strait Islander Australians, 2001 (cat. no. 4705.0). |
|(c) Estimated resident population apportioned from Statistical Local Area estimates. |
22 The reported CHINS population data are consistently higher than the Census counts on average by 32%, with one area reporting a CHINS population count 95% higher then the Census count. It can also be noted that CHINS population counts are subject to rounding by key informants, mainly due to the tendency to report a 'serviced' population and not referring to actual records when reporting.