Quality of Indigenous status data

Quality of Indigenous status data

The quality of information on Indigenous status varies among these data sources by jurisdiction and year of collection. In some areas, data presented are restricted to those states and territories where information on Indigenous status is considered of sufficient completeness for reporting. Please see details below.

Table 1.1 Availability of cancer data by Indigenous status
Data source Measure NSW Vic Qld WA SA Tas ACT NT Missing data
Australian Cancer Database Incidence Y Y Y Y N N N Y 10%
National Mortality Database Mortality Y N Y Y Y N N Y 11%
BreastScreen Australia Breast screening Y Y Y Y Y Y Y Y n.a.
National Bowel Cancer Screening Program Bowel screening Y Y Y Y Y Y Y Y n.a.
National Cervical Screening Program Cervical screening N N N N N N N N n.a.

It is not known how many Indigenous Australians are misclassified as ‘non-Indigenous’ or classified as ‘unknown’ Indigenous status in each data set. However, as some Indigenous Australians are likely to be misclassified as ‘non-Indigenous Australians’ or classified as ‘unknown’ Indigenous status, the statistics presented in this report are likely to be under-estimates. Completeness of Indigenous status classification in each data set may vary by jurisdiction, therefore comparisons should be made with caution.

Table 1.2: Completeness of Indigenous status classification in cancer data by state and territory
Years Data source Measure Indigenous status unknown (%)
2009–2013 Australian Cancer Database Incidence 16 18 10 2 n.a. 2
2011–2015 National Mortality Database Mortality 0.5 n.a. 1 0.3 0.1 0

Data footnotes

  1. Incidence, survival and prevalence data are sourced from the Australian Cancer Database.
  2. Incidence, survival and prevalence data are for New South Wales, Victoria, Queensland, Western Australia and the Northern Territory. Ninety percent of Indigenous Australians live in these five jurisdictions. This is except for analysis by Remoteness Area, where data are for New South Wales, Queensland, Western Australia and the Northern Territory due to availability of population. It excludes Victoria due to availability of population data. For Victoria population data is for major cities, inner regional and outer regional and remote combined. Eighty-three percent of Indigenous Australians live in these five jurisdictions.
  3. The Cancer Outcomes Act (2014) transferred custodianship of the Victorian Cancer Registry (VCR) to the Secretary of the Department of Health and Human Services, Victoria. This change has enabled VCR to augment the Aboriginal status data reported by hospitals for admissions relating to cancer with additional information from other administrative health datasets. This has identified nearly 100 more Aboriginal or Torres Strait Islander Victorians amongst all persons diagnosed with cancers in 2011–2015 (150,000 tumours), representing a 16% increase in cancer incidence for this period relative to that previously reported.
  4. Cancer Institute NSW has recently identified issues with its Indigenous status variable for incidence from 2008 onwards. Therefore the rates and counts reported here may not be final.

  5. Mortality data are sourced from the AIHW National Mortality Database. Cause of Death Unit Record File data are provided to the AIHW by the Registries of Births, Deaths and Marriages and the National Coronial Information System (managed by the Victorian Department of Justice) and include cause of death coded by the Australian Bureau of Statistics (ABS). The data are maintained by the AIHW in the National Mortality Database.
  6. Deaths registered in 2013 and earlier are based on the final version of cause of death data; deaths registered in 2014 and 2015 are based on revised and preliminary versions, respectively and are subject to further revision by the ABS. Actual mortality data from 1998 to 2014 are based on the year of occurrence of the death and data for 2015 are based on the year of registration of the death.
  7. Mortality data are for New South Wales, Queensland, Western Australia, South Australia and the Northern Territory. Eighty-eight percent of Indigenous Australians live in these five jurisdictions. Other jurisdictions have a small number of Indigenous deaths and identification of Indigenous deaths in their death registration systems is relatively poor, making the data less reliable.
  8. Data have been presented for multiple years to reduce random variations in rates. Exceptions to this are the incidence and mortality trends, where single years are shown to demonstrate variation in rates. Incidence data are presented for 2009 to 2013 because 2013 is the most recent year for which actual data were available for all states and territories. Mortality data are presented for 2011 to 2015.
  9. Relative survival was calculated using the period method, using the period 2007–2014. Note that this period does not contain incidence data for 2013–2014 for NSW. Data from the National Death Index (NDI) on deaths (from any cause) that occurred up to 31 December 2014 were used to determine which people with cancer had died and when this occurred. When possible, five-year relative survival is presented, however, when numbers are small, one-year relative survival is presented in text by life stage.
  10. Relative survival has not been age standardised, due to the small number of values available in each age group. Explorative analysis indicates that the difference between the Indigenous and non-Indigenous relative survival rate is likely to be larger and that the results presented are likely to be conservative.
  11. The life tables were based on enhanced Indigenous deaths which were estimated by applying Indigenous status adjustment factors to the recorded Indigenous deaths for the period in scope (2008–2014). Although all deaths are likely reported, not all Indigenous deaths are identified as Indigenous during the death registration process. This could lead to under-identification of Indigenous deaths and over-estimation of Indigenous life expectancy. This problem was dealt with by linking the National Death Index (NDI) with independent and comparative data sets that contained information on Indigenous identification. Indigenous status was compared across the linked data sets and the result of the comparison was then used in preparing Indigenous status adjustment factors. The adjustment factors were calculated separately for males and females and for each age group. The enhanced Indigenous deaths were then used in preparing Indigenous life tables using standard statistical and demographic techniques.
  12. Relative survival does not include people whose Indigenous status was not known.
  13. Some states and territories use an imputation method to determine Indigenous cancers, which may lead to differences between these data and those shown in jurisdictional cancer incidence reports.
  14. The rates were age standardised to the 2001 Australian Standard Population and are expressed per 100,000 population.
  15. All cancers combined includes cancers coded in the ICD-10 as C00–C97, D45, D46, D47.1 and D47.3–D47.5, except those C44 codes that indicate a basal or squamous cell carcinoma.
  16. Breast cancer, cervical cancer, ovarian cancer and uterine cancer are presented for females only.
  17. Prostate cancer is presented for males only.
  18. Data are presented for all cancers combined and for the following selected cancer types: bladder cancer, breast cancer (in females), cervical cancer, colorectal cancer, head and neck cancer, kidney cancer, liver cancer, lung cancer, melanoma of the skin, non-Hodgkin lymphoma, oesophageal cancer, ovarian cancer, pancreatic cancer, prostate cancer, stomach cancer, thyroid cancer, cancer of unknown primary site and uterine cancer. These cancer were selected due to high incidence or mortality for either Indigenous or non-Indigenous Australians. All other cancers, while not reported, were included in calculations for incidence, mortality and prevalence ranks. For definition of these cancers see Cancer in Australia 2017.

  19. Trend lines have been applied to figures by years based on a least-squares regression equation. Trend lines are only shown if the p-value is less than 0.05. If the p-value is greater than 0.05, a mean line is shown.
  20. Data for BreastScreen indicators are sourced from the BreastScreen register in each state and territory, according to definitions and data specifications in the BreastScreen Australia data dictionary version 1.1. These data are compiled into national figures by the AIHW to allow national monitoring of BreastScreen Australia. The Data Quality Statement for BreastScreen Australia.
  21. Data for the NBCSP indicators are sourced from the NBCSP Register data. The Data Quality Statement for the NBCSP.


  1. AIHW 2016. Australia’s health 2016. Australia’s health series no. 15. Cat. no. AUS 199. Canberra: AIHW.
  2. ABS 2017. Causes of Death, Australia, 2015. ABS Cat. No. 3303.0. Canberra Australia.