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4714.0 - National Aboriginal and Torres Strait Islander Social Survey, 2008 Quality Declaration 
Latest ISSUE Released at 11:30 AM (CANBERRA TIME) 30/10/2009   
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EXPLANATORY NOTES


Introduction

1 This publication presents summary results from the National Aboriginal and Torres Strait Islander Social Survey (NATSISS), which was conducted throughout Australia, including remote areas, from August 2008 to April 2009. This is the third social survey of Indigenous Australians conducted by the ABS. The previous NATSISS was conducted in 2002 and the first survey, the National Aboriginal and Torres Strait Islander Survey (NATSIS), was conducted in 1994.

2 A significant contribution towards the funding of the 2008 NATSISS was provided by the Council of Australian Governments (CoAG), as agreed through the Working Group on Indigenous Reform, and the Victorian Government Department of Education and Early Childhood Development (DEECD).

3 Throughout this release, the term 'Indigenous' refers to all persons who identified themselves as being of Aboriginal, Torres Strait Islander, or both Aboriginal and Torres Strait Islander origin. Information presented on Aboriginal persons includes data on persons identified as having both Aboriginal and Torres Strait Islander origin. Similarly, information on Torres Strait Islanders also includes persons identified as having both Aboriginal and Torres Strait Islander origin. An Indigenous household refers to all households with at least one Indigenous usual resident.

4 The 2008 NATSISS collected information on a range of demographic, social, environmental and economic characteristics. This release presents summary tables by three population groups:

  • Indigenous persons aged 15 years and over;
  • Indigenous children aged 4-14 years; and
  • Indigenous children aged 0-3 years.

5 This release also includes a summary table, which will enable some time-series comparisons of this survey to the 2002 National Aboriginal and Torres Strait Islander Social Survey (NATSISS). Where appropriate, additional comparisons between the 2008 and 2002 surveys have been included in the summary text.

6 This release also includes several comparison tables in the summary text, to enable non-Indigenous comparisons of this survey to the:
  • 2006 General Social Survey (GSS);
  • 2007-08 National Health Survey (NHS);
  • 2008 Survey of Education and Work (SEW); and
  • 2007-08 Survey of Income and Housing (SIH).

7 Also included are data from the monthly Labour Force Survey (LFS), based on an average of months (Aug 08-Apr 09) to enable labour force comparisons between the 2008 NATSISS and the civilian Australian population. Further explanation on the comparisons to non-Indigenous sources is provided in Appendix 1.

8 Explanations of terms and concepts are provided in the Glossary and a list of the survey's data items has been released in spreadsheet format with this publication.

9 Further information to assist in the interpretation of the survey will be provided in the National Aboriginal and Torres Strait Islander Social Survey: Users' Guide, 2008 (cat. no. 4720.0), planned for release in 2010, referred to throughout this publication as the 'Users' Guide'.


Scope and coverage of the survey

10 The scope of the survey is all Indigenous people who were usual residents of private dwellings in Australia. Private dwellings are houses, flats, home units and any other structures used as private places of residence at the time of the survey. People usually resident in non-private dwellings, such as hotels, motels, hostels, hospitals, nursing homes, and short-stay caravan parks were not in scope. Usual residents are those who usually live in a particular dwelling and regard it as their own or main home.

11 Further scope exclusions for this survey were:
  • Non-Indigenous persons;
  • Non-Australian diplomats, diplomatic staff and members of their household;
  • Members of non-Australian defence forces stationed in Australia and their dependents; and
  • Overseas visitors.

12 The survey excluded visitors to private dwellings, except for those that had been resident six months or longer. Visitors who were a usual resident of another dwelling in scope of the survey had a chance of being selected in the survey at that dwelling, or if not selected, would have been represented by similar persons who were selected in the survey.

13 The 2008 NATSISS was conducted in remote and non-remote areas in all states and territories of Australia, including discrete Indigenous communities.

14 Coverage exclusions apply to those people who were part of the in-scope population, but who were not included in the sampling frame (based on where Indigenous households were identified in the 2006 Census of Population and Housing). Coverage exclusions applied, to manage enumeration costs, included:
  • Collection Districts (CDs) with no Indigenous households;
  • Some Mesh Blocks with no Indigenous households;
  • Some remote Indigenous communities with a small number of Indigenous households; and
  • Some CDs in remote areas with a small number of Indigenous households.

15 These coverage exclusions result in an estimated undercoverage of approximately 6% of Indigenous persons in Australia. Although these areas were not enumerated, the final sample was weighted to population benchmarks to account for these exclusions. Further information on undercoverage is provided in paragraph 71 and more information on the scope and coverage of the survey will be provided in the Users' Guide, planned for release in early 2010.

16 The projected resident Indigenous population at 31 December 2008, excluding those living in non-private dwellings, was 520,350. At the same date, there were an estimated 24,400 Indigenous people living in non-private dwellings throughout Australia and approximately 200 Indigenous people considered to be migratory or living offshore.

17 Population benchmarks, which align with the survey scope, are based on projections of the most recently released Estimated Resident Indigenous Population (ERP) data, in this case, 30 June 2006. The experimental Indigenous ERP data are based on the 2006 Census of Population and Housing, adjusted by the 2006 (Census) Post-Enumeration Survey (PES). More information on the methodology used to produce the projected resident Indigenous population is available from Experimental Estimates and Projections, Aboriginal and Torres Strait Islander Australians, 1991 to 2021 (cat. no. 3238.0).


Sample design

18 The 2008 NATSISS was designed to produce reliable estimates at the national level and for each state and territory. For selected states and territories (NSW, Qld, WA and NT) the sample for children aged 0-14 years and persons aged 15 years and over was allocated to produce estimates that have a relative standard error (RSE) of no greater than 25% for characteristics that at least 5% of these populations would possess. The survey was also designed to provide reliable estimates at the national level for children aged 0-3 years, with the same RSE requirements.

19 As with previous ABS Indigenous surveys, additional sample was collected in the Torres Strait Area, to ensure data of sufficient quality would be available for the Torres Strait Area and the remainder of Queensland.

20 Funding was received from the Council of Australian Governments (CoAG) and agreed through the Working Group on Indigenous Reform to enable the collection of data on Indigenous children aged 0-14 years. Funding was also received from the Victorian Government Department of Education and Early Childhood Development (DEECD) to enable additional sample to be included for Victoria.

21 The survey design incorporated a sample of discrete Indigenous communities (including any out-stations associated with them), the 'community sample' and a sample of dwellings in areas not covered by the community sample, referred to here as the 'non-community' sample. The samples for community and non-community areas were designed separately, with each involving a multistage sampling process.

22 In Queensland (Qld), South Australia (SA), Western Australia (WA) and the Northern Territory (NT) the sample design differed by community and non-community areas.

23 In New South Wales (NSW), Victoria (Vic), Tasmania (Tas) and the Australian Capital Territory (ACT) the sample design was the same throughout, corresponding with the method used in non-community areas of the other states and territories.

24 The community sample in remote areas was obtained from a random selection of discrete Indigenous communities and out-stations using a specially developed Indigenous Community Frame. This frame was constructed using counts from the 2006 Census of Population and Housing and information collected in the 2006 Community Housing and Infrastructure Needs Survey (CHINS). All communities on this frame were in remote (or very remote) areas of Qld, SA, WA and the NT. From this frame, 71 Community Sets (containing one main community and zero or more out-stations) were selected for enumeration. A random selection of dwellings was made within the selected communities and out-stations, with different selection procedures applied to the main communities and out-stations. Within each selected dwelling, up to one Indigenous person (aged 15 years or over) and up to one Indigenous child (aged 0-14 years) was randomly selected to participate in the survey.

25 In non-community areas, dwellings were selected using a stratified multistage area sample. For the first time, Mesh Block level information within Census Collection Districts (CDs) was used to assist in targeting Indigenous people. A sample of CDs were randomly selected, with the likelihood of selection based on the number of Indigenous dwellings recorded in the area for the 2006 Census. All Mesh Blocks containing at least one Indigenous household within the CD were screened. Mesh Blocks containing no Indigenous households were either excluded on coverage or randomly sampled for screening. This approach significantly reduced screening effort in areas of low Indigenous density, such as major capital cities. In remote and very remote areas, all households were screened in selected CDs. For each randomly selected dwelling within the selected Mesh Block, one usual resident aged 18 years or over, was asked whether anyone in the household was of Aboriginal or Torres Strait Islander origin. This screening question was used to identify Indigenous households, from which the sampling process was undertaken. Where a dwelling contained one or more Indigenous usual residents, up to two Indigenous persons (aged 15 years or over) and up to two Indigenous children (aged 0-14 years) were randomly selected to participate in the survey.

26 In non-community areas, a significantly lower than expected number of households, containing Indigenous usual residents, were found after the initial screening process (described above). Therefore, additional Mesh Blocks were selected in Vic, Qld, SA, WA, Tas and the NT. Selected dwellings in these Mesh Blocks were enumerated in early 2009. The lower than expected number of households, identified as containing Indigenous usual residents, may have been due to mobility (i.e. persons moving away from the Mesh Block in which they were enumerated for the 2006 Census into areas excluded from coverage, see paragraph 14), and/or non-identification of Indigenous usual residents and non-response. Refer to paragraph 71 for more information on undercoverage.

27 After screening households in non-community areas, approximately 2.5% were identified as having an Indigenous usual resident. Of these households, 83% responded to the survey. This response rate does not take into account approximately 11% of households who were unable to be contacted and therefore establish the Indigenous status of usual residents. In communities, 78% of in-scope households were fully responding.

28 Some survey respondents provided most of the required information, but were unable or unwilling to provide a response to certain data items. The records for these persons were retained in the sample and the missing values were recorded as 'don't know' or 'not stated'. No attempt was made to deduce or impute for these missing values.

29 Further information on sample design will be provided in the Users' Guide, planned for release in early 2010.


Remoteness

30 The Australian Standard Geographical Classification (ASGC) is used by the ABS for the collection and dissemination of geographically classified statistics. For the purposes of the 2008 NATSISS, Australia is divided into five remoteness categories:
  • Major cities;
  • Inner regional area;
  • Outer regional area;
  • Remote area; and
  • Very remote area.

31 These categories are based on the Accessibility/Remoteness Index of Australia (ARIA), which measures the remoteness of a point based on the physical road distance to the nearest urban centre.

32 For this release, the remoteness categories are generally presented as:
  • Major cities;
  • Inner/Outer regional area; and
  • Remote/Very remote area.

33 Additionally, regions may also be referred to as 'remote' (includes remote and very remote) or 'non-remote' (includes major cities, inner and outer regional area).

34 More information on the ASGC is available in the Australian Standard Geographical Classification, 2008 (cat. no. 1216.0).


Data collection

35 Experienced ABS interviewers undertook personal interviews at selected private dwellings. Interviews were predominantly conducted using a Computer-Assisted Interviewing (CAI) questionnaire. CAI involves the use of a notebook computer to record, store, manipulate and transmit the data collected during interviews. For remote areas, a paper back-up of the questionnaire was available, if needed, but generally was not used.

36 Prior to enumeration, ABS interviewers participated in cultural awareness training, which provided information specifically developed for surveys involving Aboriginal and Torres Strait Islander people. The training outlined the ABS protocol for conducting surveys in community areas and described cultural considerations for interviewers.

37 In non-remote areas, questions on substance use were self-enumerated using a paper Substance Use Form. In remote areas, questions on substance use were asked by interviewers, as part of the CAI questionnaire.

38 To take account of language and cultural differences in community areas, the collection method varied for remote and non-remote areas of WA, SA, Qld and the NT. Some questions were reworded to enhance respondent understanding of the concepts (eg types of disabilities or long-term health conditions). Additionally, the survey content in remote areas excluded topics for which data quality was considered problematic to collect or not applicable.

39 In communities, where possible, ABS interviewers were accompanied by local Indigenous facilitators who assisted in the conduct of the interviews. The facilitators explained the purpose of the survey, introduced the interviewers, assisted in identifying usual residents of a household and in locating residents who were not at home. They may have also assisted respondents to understand the survey questions. A Community Information Form (CIF) was also used to collect general information from the Community Council Office to assist in the conduct of interviews in community areas.

40 Since the survey content sometimes differed in remote/non-remote areas, not all data items are available for the total Indigenous population. In the data item list, data collected only in remote areas (remote areas in WA, SA, Qld and the NT) is noted as such. There are also data items which have been adjusted to allow for remote and non-remote comparisons, which are denoted as such. For example, the disability status item is available for 'non-remote only' or as a 'remote/non-remote comparison'. For more information refer to the data item list released in spreadsheet format with this publication.

41 One person in the household, aged 18 years or over, provided basic household information, including Indigenous status, age, sex and relationships, for all household members. This person, or an elected household spokesperson, also answered some financial and housing items, such as income, tenure arrangements, community and household facilities.

42 Personal interviews were conducted with selected Indigenous persons aged 15 years and over. Exceptions occurred where the selected person:
  • was unable to complete the survey due to injury or illness (a proxy interview may have been arranged);
  • was mourning the death of a family member (Sorry Business); or
  • did not have sufficient English skills and an interpreter was unable to be arranged.

43 Where consent for interview was not given by a parent or guardian of an Indigenous person aged 15-17 years, a personal interview was not conducted.

44 Proxy interviews were used to collect information on selected Indigenous children aged 0-14 years.

45 More information on data collection and a copy of the survey questionnaire will be provided in the Users' Guide, planned for release in early 2010.


Survey content

46 Broadly, the 2008 NATSISS collected information on a range of demographic, social, environmental and economic characteristics of Indigenous people, including:
  • personal and household characteristics;
  • geography (eg state/territory and remoteness area);
  • cultural attachment (eg language and participation in cultural activities);
  • family and community experiences (eg social networks, contact and support);
  • health (eg disability or long-term conditions, risk factors, child and maternal health);
  • housing (eg tenure type and available facilities);
  • education;
  • labour force status;
  • income and financial stress;
  • use of technology;
  • transport; and
  • crime and justice.

47 A full list of data items from the survey has been released in spreadsheet format with this publication.

48 The survey was developed in consultation with numerous stakeholders, including representatives from Commonwealth and State/Territory government agencies, welfare and research agencies, peak Indigenous groups or research bodies (eg National Aboriginal Community Controlled Health Organisation and the Australian Institute of Aboriginal and Torres Strait Islander Studies), academics and prominent Indigenous researchers, and the ABS Advisory Group for Aboriginal and Torres Strait Islander Statistics.

49 Two key stakeholders were the Council of Australian Governments (COAG) Working Group on Indigenous Reform and the Victorian Government Department of Education and Early Childhood Development (DEECD), who both provided funding for the 2008 NATSISS. The DEECD also subcontracted the Onemda VicHealth Koori Health Unit to assist in developing the information requirements for Victoria.

50 More detailed results for the topics presented in this release, as well as other topics from the survey, are expected to be released on the ABS website in 2010.


Data processing

51 A combination of clerical and computer-based systems were used to process data from the 2008 NATSISS. The content of the data file was checked to identify unusual values which may have significantly altered estimates and also to assess illogical relationships not previously identified by edits. More information on data processing will be provided in the Users' Guide, planned for release in early 2010.


Weighting, benchmarking and estimation

Weighting

52 Weighting is the process of adjusting results from a sample survey to infer results for the total in-scope population. To do this, a 'weight' is allocated to each sample unit corresponding to the level at which population statistics are produced, eg person or household level. The weight can be considered an indication of how many population units are represented by the sample unit. For the 2008 NATSISS, separate person and household weights were developed.

Selection weights

53 The first step in calculating weights for each person or household is to assign an initial weight, which is equal to the inverse of the probability of being selected in the survey. For example, if the probability of being selected in the survey was 1 in 45, then the person would have an initial weight of 45 (that is, they would represent 45 people).

54 After calculating the initial person weights, an adjustment was incorporated into the weighting to account for Indigenous persons not covered by the sample. Paragraph 71 provides information on undercoverage. The initial household weights were also similarly adjusted.

Benchmarking

55 The person and household weights were separately calibrated to independent estimates of the population of interest, referred to as 'benchmarks'. Weights calibrated against population benchmarks ensure that the survey estimates conform to the independently estimated distributions of the population rather than to the distribution within the sample itself. Calibration to population benchmarks helps to compensate for over- or under-enumeration of particular categories which may occur due to either the random nature of sampling, non-response, non-identification or various other undercoverage factors. This process can reduce the sampling error of estimates and may reduce the level of undercoverage bias. More information on undercoverage is provided in paragraph 71.

56 A standard approach in ABS household surveys is to calibrate to population benchmarks by state, part of state, age and sex. In terms of the effectiveness of 'correcting' for potential undercoverage bias, it is assumed that the characteristics being measured by the survey for the covered population are similar to the uncovered population within weighting classes, as determined by the benchmarking strategy. Where this assumption does not hold, biased estimates may result.

57 For this survey, person weights were simultaneously calibrated to the following population benchmarks:
  • state by remoteness area;
  • state by age by sex;
  • Victoria by remoteness area by specific age groups by sex;
  • Torres Strait Islander status by Torres Strait Island Region by age; and
  • state by community/non-community (for this benchmark only, Qld, SA, WA and the NT had differences between community and non-community areas, see paragraph 21).

58 The survey was benchmarked to the estimated Indigenous resident population living in private dwellings at 31 December 2008. This estimated population is based on projections of the experimental estimates of the resident Indigenous population at 30 June 2006. More information on the calculation of projections is provided in Experimental Estimates and Projections, Aboriginal and Torres Strait Islander Australians, 1991 to 2021 (cat. no. 3238.0). As people in non-private dwellings (eg hotels) are excluded from the scope of the survey, they have also been excluded from the survey benchmarks. Therefore, the 2008 NATSISS estimates do not (and are not intended to) match estimates for the total resident Indigenous population obtained from other sources.

59 While estimates shown in this release are based on person weights only, household weights were also derived by calibrating the household weights to align with the person-level benchmarks, as there are no available Indigenous household benchmarks. Data at the household level is available on request, see Products and services.

Estimation

60 Estimates of counts of persons are obtained by summing person weights of persons with the characteristic of interest. The estimates presented in this release are based on benchmarked person weights.

61 More information on weighting, benchmarking and estimation will be provided in the Users' Guide planned for release in early 2010.


Reliability of estimates

62 All sample surveys are subject to error which can be broadly categorised as either:
63 Sampling error occurs because only a small proportion of the total population is used to produce estimates that represent the whole population. Sampling error can be reliably measured as it is calculated based on the scientific methods used to design surveys.

64 Non-sampling error may occur in any data collection, whether it is based on a sample or a full count (eg Census). Non-sampling error may occur at any stage throughout the survey process. For example, persons selected for the survey may not respond (non-response); survey questions may not be clearly understood by the respondent; responses may be incorrectly recorded by interviewers; or there may be errors in coding or processing survey data.

Sampling error

65 Sampling error is the expected random difference that could occur between the published estimates, derived from using a sample of persons, and the value that would have been produced if all persons in scope of the survey had been enumerated. A measure of the sampling error for a given sample estimate is provided by the standard error, which may be expressed as a percentage of the estimate (relative standard error). For more information refer to the Technical Note.

66 In this release, estimates with relative standard errors (RSEs) of 25-50% and greater than 50% have been annotated. Estimates with RSEs of 25-50% should be used with caution and those with RSEs greater than 50% are considered too unreliable for most purposes.

Non-sampling error

67 Every effort was made to minimise other non-sampling error by:
  • careful design and testing of questionnaires;
  • intensive training of interviewers; and
  • extensive editing and quality control procedures at all stages of data processing.

68 An advantage of the Computer-Assisted Interview (CAI) used for this survey is that it potentially reduces non-sampling errors by enabling edits to be applied as the data are being collected. These edits allow the interviewer to query respondents and resolve issues during the interview. Sequencing of questions is also automated so that respondents are asked only relevant questions and only in the appropriate sequence, eliminating interviewer sequencing errors.

69 Analysis was also undertaken to compare the characteristics of respondents to the 2008 NATSISS with a number of ABS collections to ascertain data consistency. Sources for comparison included:
  • 2006 Census of Population and Housing;
  • 2004-05 National Indigenous Health Survey;
  • 2002 National Aboriginal and Torres Strait Islander Social Survey; and
  • 2006 Community Housing and Infrastructure Needs Survey.

70 Further information on undercoverage and non-response is provided in the following paragraphs. More detailed information on non-sampling error will be provided in the Users' Guide, planned for release in early 2010.

Undercoverage

71 Undercoverage is one potential source of non-sampling error and is the shortfall between the population represented by the achieved sample and the in-scope population. It can introduce bias into the survey estimates. However, the extent of any bias depends upon the magnitude of the undercoverage and the extent of the difference between the characteristics of those people in the coverage population and those of the in-scope population.

72 Undercoverage rates can be estimated by calculating the difference between the sum of the initial weights of the sample and the population count. If a survey has no undercoverage, then the sum of the initial weights of the sample would equal the population count (ignoring small variations due to sampling error). For more information on weighting refer to paragraph 52.

73 In the 2008 NATSISS, there was a relatively large level of undercoverage when compared to other ABS surveys. There was also an increase in undercoverage compared to previous ABS Indigenous surveys.

74 The overall undercoverage rate is approximately 53% of the population at the national level. This rate varies across the states and territories, with a rate of up to 62% in the Northern Territory. Of the national rate, 6% is due to planned frame exclusions and overlap with the Monthly Population Survey where analysis has shown that the impact of any bias is minimal. More information on these exclusions is provided below.

75 Given the high undercoverage rate, the analysis undertaken to ensure that results from the 2008 NATSISS were consistent with other data sources was more extensive than usual. Examples of the sources used for consistency checks are outlined in paragraph 69 and more information on the validation of survey data will be provided in the Users' Guide planned for release in early 2010.

76 Briefly, potential bias due to undercoverage was addressed by the application of:
  • a number of adjustments to the initial weights - the weights were calibrated to population benchmarks to account for the undercoverage at the various calibration levels; and
  • an adjustment to geographical areas based on the density of the Indigenous population - to account for the different undercoverage rates and the characteristics of Indigenous persons living in these areas.

77 More information on the measures taken to address potential bias will be provided in the Users' Guide planned for release in early 2010.

78 Undercoverage may occur due to a number of factors, including:
79 Each of these factors are outlined in more detail in the following paragraphs. To assist interpretation, a diagrammatical representation of the potential sources of undercoverage is also provided.

Diagram: 2008 NATSISS - Potential sources of undercoverage

Frame exclusions

80 Frame exclusions were incorporated into the 2008 NATSISS to manage the cost of enumerating areas with a small number of Indigenous persons. There were also unplanned exclusions on the non-community frame, due to an error in identifying private dwellings during the creation of the frame. This error resulted in the undercoverage of some discrete Indigenous communities, which were not represented in the survey's community sample. More information on scope and coverage is provided in paragraph 14.

81 At the national level it is estimated that 8.5% of the in-scope population was excluded from the frame. Part of this exclusion represents an estimate of the people who had moved since the 2006 Census. The number of people who moved may be higher than estimated and could account for a portion of the higher than expected non-identification estimate discussed in paragraph 87.

Non-response

82 Non-response may occur when people cannot or will not cooperate, or cannot be contacted. Unit and item non-response by persons/households selected in the survey can affect both sampling and non-sampling error. The loss of information on persons and/or households (unit non-response) and on particular questions (item non-response) reduces the effective sample and increases both sampling error and and the likelihood of incurring response bias.

83 To reduce the level and impact of non-response, the following methods were adopted in this survey:
  • face-to-face interviews with respondents;
  • local Indigenous facilitators were employed to assist with interviewing in communities;
  • follow-up of respondents if there was initially no response; and
  • ensuring the weighted file is representative of the population by aligning the estimates with population benchmarks.

84 In the 2008 NATSISS, non-response accounts for a portion of overall undercoverage. The two components of non-response were:
  • non-response to the screening question; and
  • non-response to the survey after identification of an Indigenous household.

85 Of the households screened in non-community areas, approximately 89% of Indigenous households responded. This assumes that response to the screening question is not related to the Indigenous status of the household. Of households who responded to the screening question, approximately 2.5% were identified as having an Indigenous usual resident. Of these identified households, around 83% then responded to the survey.

86 In discrete Indigenous communities, 78% of selected in-scope households were fully responding.

Non-identification as Indigenous

87 Non-identification of Indigenous households during the screening process may have occurred due to:
  • Indigenous people not identifying themselves as Indigenous (passive refusals); or
  • the household spokesperson being unaware of (or unwilling to provide) the Indigenous status of other residents.

88 The under-identification of Indigenous persons in non-community areas is estimated to be up to 31% of those screened. This estimate is the remaining level of undercoverage when all other known sources of undercoverage have been removed. Part of this proportion is likely to be due to other factors which are unknown.

Issues arising in the field

89 Known undercoverage, due to other issues arising in the field, included sample being excluded due to:
  • overlap with the Monthly Population Survey; and
  • occupational, health and safety issues.

90 The estimated undercoverage due to these issues was 3.7% at the national level.


Seasonal effects

91 The estimates in this publication are based on information collected from August 2008 to April 2009, and due to seasonal effects they may not be fully representative of other time periods in the year. For example, the 2008 NATSISS asked people if they had participated in any physical, sporting, community or social activities in the three months prior to interview. Involvement in particular activities may be subject to seasonal variation through the year. Therefore, the results could have differed if the survey had been conducted over the whole year or in a different part of the year.


Interpretation of results

92 Care has been taken to ensure that the results of this survey are as accurate as possible. All interviews were conducted by trained ABS officers. Extensive reference material was developed for use and intensive training was provided to interviewers. There remain, however, other factors which may have affected the reliability of results, and for which no specific adjustments can be made. The following factors should be considered when interpreting these estimates:
  • Information recorded in this survey is 'as reported' by respondents, and therefore may differ from information available from other sources or collected using different methodologies;
  • Responses may be affected by imperfect recall or individual interpretation of survey questions; and
  • Some respondents may have provided responses that they felt were expected, rather than those that accurately reflected their own situation.

93 Every effort has been made to minimise such bias through the development and use of culturally appropriate survey methodology.

94 For a number of survey data items, some respondents were unwilling or unable to provide the required information. Where responses for a particular data item were missing for a person or household they were recorded in a 'not known', 'not stated' or 'refusal' category for that data item. In some instances, 'not stated' categories have been included in the publication tables, to enable users to determine the suitability of the data for their purposes. For example, more than 10% of Indigenous persons were unable or unwilling to answer whether they had relatives who had been removed from their natural families. Given this proportion applied nationally, by remoteness and states or territory, a separate 'not stated' category has been provided for this item. In some instances, 'not stated' categories are not explicitly shown in the tables, but are included in the total or are grouped with another output category. These groupings are indicated by footnotes. Tables presenting proportions include 'not known' or 'not stated' categories in the calculation of these proportions.

95 Different data items were collected for different time periods, eg labour force status is based on the week prior to interview, level of psychological distress relates to the 4 weeks prior to interview and alcohol consumption refers to the 12 months prior to interview. The reliability and accuracy of data are therefore dependent on the respondent's recall.

96 Results of previous ABS surveys and administrative data collections on use of alcohol and illegal drugs suggest a tendency for respondents to under-report actual consumption levels.

97 The employment component of the 2008 NATSISS is based on a reduced set of questions from the ABS monthly Labour Force Survey.

98 Information on the age standardisation technique used in this publication is provided in the Technical Note.

99 Broad information to assist the interpretation of specific topics in this publication is provided in the following paragraphs. Further information will be provided in the Users' Guide planned for release in early 2010.

Household composition and family living arrangements

100 Due to the complexity of living arrangements of Indigenous households, the data presented may not entirely reflect all persons' circumstances. For example, households may include several members of 'extended family', for which the relationships in the household may be difficult to ascertain.

Social and emotional wellbeing

101 The 2008 NATSISS contains a series of questions on social and emotional wellbeing in the 4 weeks prior to interview, based on selected items from two well-known survey instruments:
102 The survey also contains questions related to personal stressors, discrimination, social support and cultural identification.

103 The K10 is a widely used screening instrument, which gives a simple measure of psychological distress based on a person's emotional state during the 4 weeks prior to interview. It is not a diagnostic tool, but is an indicator of psychological distress. This survey collected responses to five of the K10 questions, producing outputs for what will be referred to as a K5.

104 Briefly, respondents were asked a series of five questions and for each item, they provided a five-level response scale, based on the amount of time they reported experiencing a particular feeling. Responses to the five questions were put together, resulting in a minimum possible score of 5 and a maximum possible score of 25. Low scores indicate low levels of psychological distress and high scores indicate high levels of psychological distress.

105 The SF-36 is an instrument designed to provide information on general health and wellbeing across eight dimensions, including: physical functioning; role limitations due to physical problems; bodily pain; general health perceptions; vitality; social functioning; role limitations due to emotional problems; and mental health. The 2008 NATSISS includes four questions on positive aspects of social and emotional wellbeing in the 4 weeks prior to interview. Data from the SF-36 are not presented in this release, but may be available on request, refer to Products and services.

Disability

106 In the 2008 NATSISS, the questions used to ascertain disability status and disability type differed for persons living in remote and non-remote areas. In remote areas, the wording of screening questions to establish disability status was less detailed and respondents were not specifically asked whether they had any mental illness for which help or supervision was required. These differences possibly result in an underestimate of Indigenous persons with a disability in remote areas. Although the survey did not explicitly identify persons in remote areas with a mental illness, some people may have been identified as having some other type of disability and therefore are included in the total of persons with a disability.

107 In tables containing disability data, the population is limited to the set of criteria used to identify disability in remote areas, to enable comparable data from remote and non-remote areas to be presented. The data are therefore not strictly comparable to non-Indigenous data, which include people with a mental illness for which help or supervision is required.

108 More detailed disability information for persons in non-remote areas may be available on request, refer to Products and services.

Major structural problems

109 In the 2008 NATSISS, rising damp was only included as a major structural problem in non-remote areas. Therefore, to allow the presentation of data for both remote and non-remote areas, households in non-remote areas whose only major structural problem was rising damp have been excluded.


Comparability with other ABS data sources

110 To aid comparability with other ABS data sources, where possible, questions from existing surveys were used in the 2008 NATSISS questionnaire. However, due to the number of topics included in this survey, it was not always possible to adopt the full question modules used in other surveys. In addition, some modules were further shortened or omitted in community areas because they were not relevant or not able to be effectively administered for the NATSISS within these areas. Where possible, the 2008 NATSISS used standard ABS 'shortened' question modules, designed to maximise comparability with the full question modules.

111 Results from the 2008 NATSISS may differ from other ABS surveys which collect information on the same topics as the information is based on a sample of the population and are subject to sampling variability (or sampling error). For example, results from this survey may differ from the figures that would have been obtained from an enumeration of the entire population (eg Census). More information on sampling error is provided in the Technical Note.

112 Differences may also exist in the scope and/or coverage of this survey compared to other surveys. For example, the 2008 NATSISS includes Indigenous people living in private dwellings across Australia, including remote and very remote areas, whereas the 2007-08 National Health Survey includes people living in private dwellings across Australia, excluding remote areas. Another example is the monthly Labour Force Survey, which includes people aged 15 years and over who live in private dwellings, but also includes a sample of people resident in non-private dwellings (eg hotels).

113 The collection period for this survey was August 2008 to April 2009. The results may therefore differ to other surveys conducted during different reference periods, due to seasonal effects. See paragraph 91 for more information.

114 Differences in estimates may also occur as a result of different collection methodologies. For example, if the information was:
  • collected through a personal interview;
  • self-enumerated by the respondent;
  • provided by the person themselves; or
  • was collected from a proxy.

115 Differences may also result from the context in which questions are asked (eg ordering of the questions or the type of survey being conducted). Additionally, self-identification of Indigenous status may vary, depending on the collection methodology (eg face-to-face interview compared to a self-completed form).

116 Further information on the comparability of the 2008 NATSISS to other ABS sources is provided in Appendix 1.

Comparability with previous Indigenous Social Surveys

117 The ABS previously conducted the National Aboriginal and Torres Strait Islander Social Survey (NATSISS) in 2002. A National Aboriginal and Torres Strait Islander Survey (NATSIS) was also conducted in 1994. Extensive information on the differences between the 2002 and 1994 surveys is provided in the Explanatory Notes of the National Aboriginal and Torres Strait Islander Social Survey, 2002 (cat. no. 4714.0).

118 This release contains selected data from the 2002 NATSISS. Data have been limited to items where there is a sufficient level of comparability between the 2008 and 2002 surveys.

119 Understanding the extent to which data from the 2008 and 2002 NATSISS can be compared is essential in interpreting apparent changes over time. While many key data items in the 2008 survey are the same or similar to those in the 2002 survey, there are differences in the sample design and coverage, survey methodology and content, definitions, and classifications, all of which may impact on comparability.

120 The scope of the NATSISS changed between 2002 and 2008, to enable the inclusion of Indigenous children aged 0-14 years. While this change does not specifically impact on the comparability of data for Indigenous adults aged 15 years and over, some survey modules and questions were redeveloped and/or expanded to include Indigenous children. Briefly, the information collected on Indigenous children includes:
  • language and culture (eg participation in activities and time spent with elders)
  • child health (eg general health, nutrition, physical activity, dental and sleep);
  • maternal health of children aged 0-3 years (eg high blood pressure during pregnancy); and
  • education of children aged 0-14 years (eg school attendance and informal learning).

121 For the first time, the 2008 NATSISS used Mesh Block level information within Census Collection Districts to assist in targeting Indigenous people. More information on this process is provided in paragraph 25.

122 There are minor differences between the data available on major structural problems from the 2002 and 2008 NATSISS. In 2008, rising damp was only included as a major structural problem in non-remote areas. In 2002, rising damp was only included as a major structural problem for households in non-community areas. As there were a small number of remote non-community households that reported rising damp as a major structural problem in 2002, these have been excluded from the summary table to enable comparisons of like data. Therefore, data presented in this release differs slightly to the data presented in the 2002 publication.

123 Disability status also differs between the two surveys. In 2008, two additional response categories were included for people in remote areas:
  • Any condition such as back problems or bad headaches, that stop or reduce your being able to do any physical activity or work; and
  • Any scars, loss of limbs or other conditions that affect your appearance.

124 There were also two additional long-term conditions in the 2008 survey for people in remote areas:
  • Fears or any emotional problems, such as depression, that make doing things hard; and
  • A long-term health condition such as arthritis, asthma, heart disease, diabetes/sugar problems or kidney problems.

125 Further information on the comparability of the 2002 and 2008 NATSISS will be provided in the Users' Guide planned for release in early 2010. Broad differences in the design of the two surveys are summarised in the following table.

COMPARISON TO THE 2002 NATSISS, by survey design

2008 NATSISS 2002 NATSISS

Collection methodology

Computer-assisted interview (CAI). In remote areas a paper back-up of the questionnaire was available in case of technical difficulties. Computer-assisted interview (CAI) for non-remote areas, and remote areas in NSW, Victoria and Tasmania.
- Pen and paper interviews (PAPI) for remote areas not covered by CAI.
Selected persons and proxies in remote and non-remote areas were given the option of using prompt cards. The respondent could read directly from the cards or the card may have been read aloud by the interviewer. Prompt cards were used in non-remote areas only.
In non-remote areas, selected persons aged 15 years and over were provided with a self-enumerated substance use form. In non-remote areas, the substance use questions were completed by the selected person using a voluntary self-enumerated form.
Personal interview for persons aged 15 years and over (where consent was not given for persons 15-17 years, an interview was not conducted). Personal interview for persons aged 15 years and over (where consent was not given for persons 15-17 years, an interview was not conducted).
A proxy interview was conducted for children aged 0-14 years, people unable to complete the survey due to injury or illness and people who did not have sufficient English skills (an interpreter may have been used). -
A household spokesperson aged 18 years and over provided household information, including: community facilities, bedrooms, telephone/IT access, transport, household facilities, maintenance, tenure, financial stress and income. A household spokesperson aged 18 years and over provided household information, including dwelling, financial situation of household and income for people not selected for personal interview.

Scope

Indigenous persons (all ages) Indigenous persons aged 15 years and over
Usual residents of private dwellings in remote and non-remote areas of Australia. Usual residents of private dwellings in remote and non-remote areas of Australia.

Sample design

For selected households in discrete remote Indigenous communities and outstations: one Indigenous person aged 15 years and over and one child aged 0-14 years. For selected households in non-remote and remote non-community areas: up to two Indigenous persons aged 15 years and over and up to two children aged 0-14 years. Up to three Indigenous persons aged 15 years and over per household.

Final sample

13,307 persons (7,823 adults and 5,484 children) 9,359 persons (aged 15 years and over)

Response rate

82% of households in non-community and community areas Approx 80% of households in non-community and community areas

Enumeration period

August 2008-April 2009 August 2002-April 2003

Main output units

Persons Persons
Household Household

Exclusions

Non-Indigenous persons Non-Indigenous persons
Non-Australian diplomats, dipomatic staff and members of their household Visitors
Members of non-Australian defence forces stationed in Australia and their dependents -
Overseas visitors -




Classifications

126 Geography data were classified according to the Australian Standard Geographical Classification (ASGC), Jul 2008 (cat. no. 1216.0).

127 Languages spoken were coded utilising the Australian Standard Classification of Languages (ASCL), 2005-06 (cat. no. 1267.0).


Products and services

128 For users who wish to undertake more detailed analysis of the survey data, an Expanded Confidentialised Unit Record File (CURF) is expected to be released in early 2010. The Expanded CURF will be accessible through the ABS Remote Access Data Laboratory (RADL) system. Further information about this file, including how it can be obtained and the conditions of use, is available through the CURF Microdata Entry Page on the ABS website.

129 Summary of the products to be released in early 2010:
130 A list of data items from the 2008 NATSISS has been released in spreadsheet format with this publication.

131 A copy of the survey questionnaire and prompt cards will be provided with the Users' Guide planned for release in early 2010.

132 More detailed results for the topics presented in this release, as well as additional topics from the survey, are expected to be released on the ABS website in 2010.

133 To return the survey's information to Aboriginal and Torres Strait Islander people, a series of thematic releases are planned for distribution (in printed format) to Indigenous communities, organisations and schools. Further information will be available on the ABS website.

134 Special tabulations based on the data from this survey are available on request. Subject to confidentiality and sampling variability constraints, tabulations can be produced from the survey to meet individual requirements. These can be provided in electronic or printed form.

135 For more information about this survey and associated products contact the National Information and Referral Service on 1300 135 070 or the National Centre for Aboriginal and Torres Strait Islander Statistics on 1800 633 216 or email ncatsis@abs.gov.au.


Acknowledgment

136 The 2008 NATSISS was dependent on the high level of cooperation received from Aboriginal and Torres Strait Islander peoples and their communities. Without their continued cooperation, the wide range of Indigenous statistics published by the ABS would not be available. Information received by the ABS is treated in strict confidence as required by the Census and Statistics Act 1905.


Related publications

137 Current ABS publications and other products available from the ABS website, include:

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