Aboriginal and Torres Strait Islander Health Performance Framework (HPF) 2012

Technical Appendix—Main sources

The HPF was designed to measure the impact of the National Strategic Framework for Aboriginal and Torres Strait Islander Health (NSFATSIH) and will be an important tool for developing the new National Aboriginal and Torres Strait Islander Health Plan (NATSIHP).

Page last updated: 15 November 2012

The data in this report are mainly drawn from national data collections and surveys. These include the following:

The National Aboriginal and Torres Strait Islander Social Survey (NATSISS):

The 2008 NATSISS was conducted between August 2008 and April 2009. Information was collected by personal interview from approximately 13,300 Aboriginal and Torres Strait Islander people; 5,500 aged 0–14 years and 7,800 aged 15 years and over in both non-remote and remote parts of Australia. The NATSISS sample was specifically designed to select a representative sample of Aboriginal and Torres Strait Islander peoples. The NATSISS uses the standard Indigenous status question to identify Aboriginal and Torres Strait Islander households from which the sampling process is then undertaken. Information recorded in this survey is 'as reported' by respondents, or from child proxies (usually parents), on behalf of selected children aged 0–14 years. Data may differ from those which might be obtained from other sources or by using other collection methodologies. Responses may also be affected by imperfect recall or individual interpretation of survey questions. Selected non-Indigenous comparisons are available from the 2007–08 National Health Survey and a range of other surveys. Further details can be obtained from ABS cat. no. 4714.0 ABS 2009. Time-series comparisons for some indicators are available from the 2002 NATSISS and the 1994 National Aboriginal and Torres Strait Islander Survey (NATSIS).

National Aboriginal and Torres Strait Islander Health Survey (NATSIHS):

The 2004–05 NATSIHS included a sample of 10,439 Aboriginal and Torres Strait Islander people. This was considerably larger than the supplementary Aboriginal and Torres Strait Islander peoples samples in the 1995 and 2001 National Health Surveys (NHS) (3,681 in 2001). The NATSIHS sample was specifically designed to select a representative sample of Aboriginal and Torres Strait Islander peoples and thus overcome the problem inherent in most national surveys (i.e., small and unrepresentative samples). Information recorded in this survey is 'as reported' by respondents. Responses may be affected by imperfect recall or individual interpretation of survey questions. Any data that are self-reported are also likely to underestimate circumstances about which the respondent is unaware, or may be reluctant to report (e.g., certain health conditions, weight, drug use). Computer assisted interviewing (CAI) was used in non-remote areas and paper forms were used in remote areas. Selected non-Indigenous comparisons are available from the 2004–05 National Health Survey (NHS). The NHS was conducted in major cities, regional and remote areas, but very remote areas were excluded from the sample. Further information on NATSIHS data quality issues can be found in the national publication ABS cat. no. 4715.0 (ABS 2006b).Top of page

Census:

The Census uses the standard Indigenous status question and it is asked for each household member.

There are four principal sources of error in Census data: respondent error, processing error, partial response and undercount. Quality management of the Census program aims 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.

The Census form may be completed by one household member on behalf of others. Incorrect answers can be introduced to the Census form if the respondent does not understand the question or does not know the correct information about other household members. Many of these errors remain in the final data.

The processing of information from Census forms is now mostly automated. Quality assurance procedures are used during Census processing to ensure processing errors are minimised. Sample checking is undertaken during coding operations, and corrections are made where necessary.

When completing their Census form, some people do not answer all the questions which apply to them. In these instances, a 'not stated' code is allocated during processing, with the exception of non-response to age, sex, marital status and place of usual residence. These variables are needed for population estimates, so they are imputed using other information on the Census form, as well as information from the previous Census.

Other Census data issues relate to the accuracy of the Census count itself, e.g., whether people are counted more than once, or not at all.

The significant volatility in Aboriginal and Torres Strait Islander Census counts and the variable quality of data on births, deaths and migration of Aboriginal and Torres Strait Islander peoples do not support the use of the standard approach to population estimation. Due to the inherent uncertainties in estimating the Aboriginal and Torres Strait Islander population, data which use these estimates should be interpreted with caution (e.g., life expectancy estimates, mortality rates). Given these uncertainties, changes in health outcomes such as mortality rates are difficult to assess over the long term.

Following each Census, assumptions are made about past levels of mortality to produce back cast population estimates.

A comparison of mortality rates using 2001 Census-based estimates and 2006 Census-based estimates produce different results. A number of investigations were undertaken to seek to understand the results and recommend options for future reporting on trends. This analysis found significant problems with the 2001 based estimates, particularly with the older age groups. In this report, trend analysis is based on 2006 Census back cast estimates and projections (Series B).Top of page

In the 2011 Census, the ABS implemented improvements to the 2011 Census Indigenous enumeration procedures and enhanced the Census Post Enumeration Survey.

National Perinatal Data Collection:

Birth notification forms are completed for all births of 20 weeks or more gestation, or a birthweight of 400 grams or more. The Perinatal National Minimum Data Set includes all births in Australia in hospitals, birth centres and the community. State-level data are based on place of mother's usual residence rather than place where birth occurred. Complicated pregnancies from surrounding NSW may be referred to the ACT and hence there may be poorer outcomes attributed to ACT births. Because of this and the small numbers involved, care should be taken in interpreting data from the ACT (Laws et al. 2004). A standard data item for Indigenous status is specified in the Perinatal National Minimum Data Set. However, at this stage not all states and territories use this standard wording for the Indigenous status question on their forms. This impacts on the quality and comparability of the data collected (ABS & AIHW 2005). Data on Indigenous status are not reported for Tasmania prior to 2005, as the not stated category for Indigenous status was included with the non-Indigenous category. All jurisdictions collect Indigenous status of the mother for each baby. A data item on Indigenous status of the baby will be added to the Perinatal National Minimum Data Set from July 2012.

Studies in Australia linking perinatal data with birth registration data and hospital admissions show that Aboriginal and Torres Strait Islander data are under-reported (Taylor et al. 2000; Comino et al. 2007; Kennedy et al. 2009). In 2007, the AIHW completed an assessment of the quality of Indigenous status information in perinatal data in each state and territory. This involved a survey which was sent to the midwifery managers across Australia to determine how many hospitals in each jurisdiction obtain Indigenous status information of mothers giving birth from admission records and how many collect this information independently. The assessment also involved analysis of the variability in the number and proportion of mothers recorded as Aboriginal and/or Torres Strait Islander in the perinatal data collection over time and across jurisdictions for the period 1991–2004. The outcomes of this assessment showed that Indigenous status data from NSW, Victoria, Queensland, WA, SA and the NT are suitable for trends analysis and national reporting. Perinatal data from Tasmania, although improving, were deemed to be of insufficient quality. Although the most recent data in the ACT were of publishable quality, the data were not yet of sufficient stability to support trends analysis (AIHW: Leeds KL et al. 2007).

All jurisdictions are working towards improving the quality of Indigenous status in perinatal data collections. States and territories have agreed to improve Aboriginal and Torres Strait Islander data collection procedures in key data collections including implementation of the Best Practice Guidelines for the collection of Indigenous status in health data sets.

AIHW is working with the states and territories in the development of an enhanced Perinatal National Minimum Data Set to include nationally consistent data items on antenatal care, smoking and alcohol use during pregnancy, and Indigenous status of the baby. Nationally consistent data items on smoking during pregnancy, gestational age at first antenatal visit, and Indigenous status of the baby have been added to the Perinatal NMDS (from 1 July 2009, 1 July 2010, and 1 July 2012 respectively). A data item on number of antenatal visits will be included in the Perinatal NMDS from 1 July 2013. Work is underway to progress data elements related to alcohol use in pregnancy.Top of page

National Hospital Morbidity Data:

This is a data collection including all completed admitted patient episodes in public and private hospitals across Australia. The number and pattern of hospitalisations can be affected by differing admission practices among the jurisdictions and from year to year, and differing levels and patterns of service delivery. Some jurisdictions have slightly different approaches to the collection and storage of the standard Indigenous status question and categories in their hospital collections. The incompleteness of Indigenous identification means the number of hospital separations recorded as Aboriginal and Torres Strait Islander is an underestimate of hospitalisations involving Aboriginal and Torres Strait Islander people. For several years, Queensland, SA, WA and the NT reported that Indigenous status in their hospital separations data was of acceptable quality (AIHW 2007). Between 2006 and 2008, the AIHW completed an assessment of the level of Indigenous under-identification in selected public hospitals in all states and territories. Results from this assessment indicate that NSW, Victoria, Queensland, WA, SA and the NT have adequate Indigenous identification (20% or less overall under-identification of Aboriginal and Torres Strait Islander patients) in their hospital separations data. It has therefore been recommended that reporting of data on hospital separations by Aboriginal and Torres Strait Islander peoples be limited to aggregated information from NSW, Victoria, Queensland, WA, SA and the NT. Tasmania and ACT data are presented at the state/territory level and should be used with caution, but they are not aggregated with the other 6 jurisdictions.

Interpretation of results should take into account the relative quality of the data from the jurisdictions.

The proportion of the Aboriginal and Torres Strait Islander population covered by the six jurisdictions is 96% (AIHW 2010g). Hospitalisation data for these six jurisdictions should not be assumed to represent the hospitalisation experience in the ACT and Tasmania.

From the 2007 AIHW study it was possible to produce correction factors for the level of Indigenous under-identification in hospital data at the national level. In 2011–12, the AIHW commenced another study to re-assess the level of under-identification in public hospitals data. All states and territories have participated in the study to assess improvements in data quality. A report on the findings is expected to be published in late 2012, which will include new correction factors for the level of Indigenous under-identification in hospital separations data at the national, state/territory and remoteness levels.

Hospitalisations for which the Indigenous status of the patient was not reported are excluded from hospitalisations data for non-Indigenous Australians, apart from WA where records with an unknown status are recorded as non-Indigenous.

National Mortality Database:

The count of deaths for Aboriginal and Torres Strait Islander peoples can be influenced by the accuracy of identification of Aboriginal and Torres Strait Islander deaths, late registration of deaths, as a result of coronial inquiry, and changes to death forms and/or processing systems. Due to the small size of the Aboriginal and Torres Strait Islander population these factors can significantly impact on trends over time and between jurisdictions.Top of page

All jurisdictions comply with the standard wording for the Indigenous status question and categories for their death registration forms. However, Victoria, SA, the NT and the ACT all have slightly different wording to the national standard for the instruction on those with both Aboriginal and Torres Strait Islander origin (ABS & AIHW 2005).

Almost all deaths in Australia are registered. However, the Indigenous status of the deceased is not always recorded/reported and/or recorded correctly. The incompleteness of Indigenous identification means the number of deaths registered as Aboriginal and Torres Strait Islander is an underestimate of deaths occurring in the Aboriginal and Torres Strait Islander population (ABS 1997). As a result, the observed differences between Aboriginal and Torres Strait Islander and non-Indigenous mortality are underestimates of the true differences.

The number of deaths registered in Qld in 2010 was exceptionally high due to the late registrations of deaths which occurred prior to 2007, most of which were for Aboriginal and Torres Strait Islander deaths. For reporting in the 2012 HPF, the Qld 2010 deaths were adjusted in order to minimise the impact of late registration of deaths on mortality indicators. All deaths that were registered in Qld in 2010 that occurred prior to 2007 were excluded. This is consistent with reporting by the ABS in their causes of death publication.

Western Australian Aboriginal and Torres Strait Islander deaths for 2007, 2008 and 2009, were initially over-reported. The ABS and relevant stakeholders including the AIHW and WA authorities have investigated the issues and establish solutions to rectify the problem. Updated WA mortality data for these years (including aggregates of years and single year time series) have been included in the 2012 HPF.

While the identification of Aboriginal and Torres Strait Islander peoples in deaths data is incomplete in all state and territory registration systems, five jurisdictions (NSW, Queensland, WA, SA and the NT) have been assessed by the ABS and the AIHW as having adequate identification. Longer term mortality trend data are limited to three jurisdictions (WA, SA and the NT) with adequate identification of Aboriginal and Torres Strait Islander deaths in their recording systems from 1991 onwards. The quality of the time-series data is also influenced by the late inclusion of a not stated category for Indigenous status in 1998. Prior to this time, the not stated responses were probably included with the non-Indigenous. The ABS calculated the identification rate of Aboriginal and Torres Strait Islander deaths for the period 2006–07 through data linkage between the Census and death registration records to examine differences in reporting of Indigenous status across the two datasets (ABS 2009b). Top of page
Aboriginal and Torres Strait Islander deaths identification rate, state/territory and Australia, 2006–07
State/territoryIdentification Rate
NSW
0.87
Qld
0.94
WA
1.11
NT
1.09
Vic, SA, Tas, ACT, Overseas territories
0.65
Australia
0.92
Source: ABS 2009

As part of the data development work funded under the NIRA, the ABS will link Census records with death registration records to assess the level of identification again in relation to the 2011 Census.

The AIHW is also undertaking a project to develop an Enhanced Mortality Database by linking death registration records to several additional data sources that contain information on Aboriginal and Torres Strait Islander deaths (hospital, perinatal and residential aged-care data). The enhanced data are expected to enable more accurate estimates of Aboriginal and Torres Strait Islander mortality, including life expectancy, to be made. Results from phase 1 of the project, which linked data for the period 2001 to 2006, produced national estimates of Aboriginal and Torres Strait Islander life expectancy at birth of 66.6 years for males and 72.7 for females, which was similar to the estimates produced by the ABS (AIHW 2012c).

States and territories have agreed to the implementation of the Best Practice Guidelines for the collection of Indigenous status in health data sets.

BEACH

The Bettering the Evaluation And Care of Health (BEACH) survey collects information about consultations with GPs, including GP and patient characteristics, patient reasons for the visit, problems managed and treatments provided. The survey has been conducted annually since April 1998. Information is collected from a random sample of approximately 1,000 GPs from across Australia each year. Each GP provides details of 100 consecutive consultations.Top of page

Although the questionnaire contains an Indigenous identifier, it is unknown whether all GPs ask their patients this question. In a sub-study, Supplementary Analysis of Nominated Data of approximately 9,000 patients, it was found that if the question on Indigenous status was asked within the context of a series of questions about origin and cultural background, 1.3% identified as Aboriginal and Torres Strait Islander. This is twice the rate routinely recorded in BEACH, indicating that BEACH may under-estimate the number of Aboriginal and Torres Strait Islander consultations.

Under the NIRA, governments have agreed to the implementation of the Best Practice Guidelines for the collection of Indigenous status in health data collection, which include recommended strategies for local service providers such as GPs and practice nurses to improve Indigenous identification data.

The Commonwealth's contribution to the National Partnership Agreement on Closing the Gap in Indigenous Health Outcomes is the Indigenous Chronic Disease Package, which includes a number of measures that encourages GPs to identify their Aboriginal and Torres Strait Islander clients. General practices and Aboriginal and Torres Strait Islander health services that meet accreditation requirements are eligible for financial incentives when they sign-on to the Practice Incentives Program—Indigenous Health Incentive (IHI), obtain consent from their Aboriginal and Torres Strait Islander clients to be registered for chronic disease management through the IHI, and provide a targeted level of care for each registered patient. Participation in the PIP IHI also provides eligibility for other initiatives under the Indigenous Chronic Disease Package such as the Care Coordination and Supplementary Services Program.

Community Housing and Infrastructure Needs Survey (CHINS):

The CHINS collects data about discrete Aboriginal and Torres Strait Islander communities. In 2006, a total of 1,187 communities were surveyed, with a combined usual population of 92,960 Aboriginal and Torres Strait Islander peoples or 18% of the total estimated Aboriginal and Torres Strait Islander population. The survey was also conducted in 2001 and 1999. The data are collected from key personnel in Aboriginal and Torres Strait Islander communities and housing organisations knowledgeable about housing and infrastructure issues. This collection is not a population survey.Top of page