In 2008, the Council of Australian Governments (COAG) agreed to reduce the gap in life expectancy between Indigenous and non-Indigenous Australians. Robust measures of Indigenous mortality are needed to monitor the success, or otherwise, of government and community efforts to reduce the gap.

There is imperfect identification of Indigenous deaths in the key data sets used in preparing Indigenous life tables and mortality estimates. As a result, the true mortality characteristics of Indigenous Australians cannot be reliably measured.

The aim of the Enhanced Mortality Database project is to improve information on Indigenous status on the registered deaths data set by linking it to several additional data sources that contain information on Indigenous deaths and Indigenous identification. The enhanced data are expected to enable more accurate estimates of Indigenous mortality, including life expectancy, to be made. This study will also show whether such data linkage work is feasible and whether the results are credible.

The additional data sets are the Residential Aged Care (RAC) data set, the National Hospital Morbidity Database (NHMD) and the National Perinatal Data Collection (NPDC). The quality of these data sets varies between states and territories.

An ‘ever-Indigenous‘ approach was used in determining Indigenous status from the various data sets. The approach accepts that the deceased was Indigenous if indicated by any of the data sets.

The death registration data set (2001–2006) used for this project contained 10,547 deaths listed as Indigenous. The linkage of the additional data sets to the death registration data set identified 1,081, or 10.2%, more deaths than the 10,547 originally recorded on the death registration data set as ‗Indigenous‘. Of the additional Indigenous deaths, 74.5% were from the National Hospital Morbidity Database, 24% from the Residential Aged Care data set and 1.5% from the National Perinatal Data Collection.

Using these linked data sets produces national estimates of Indigenous expectation of life at birth, of 66.6 years for males and 72.7 for females for the period 2001–2006. These estimates are close to estimates of 67.2 years for Indigenous males and 72.9 for Indigenous females, prepared by the ABS from the Mortality Quality Study, which was conducted as part of the 2006 Census Data Enhancement Study.

Although data from all states and territories were linked and used in preparing the Indigenous life tables for Australia, separate life tables were only prepared for New South Wales, Victoria, Queensland, Western Australia, South Australia and the Northern Territory. This was because the number of Indigenous deaths in Tasmania and the Australian Capital Territory were too few to enable reliable life tables to be constructed.