The Enhanced Mortality Database (EMD) was developed in 2010 by the Australian Institute of Health and Welfare to explore the feasibility of creating an ongoing enhanced mortality data set that allows analysis of key mortality indicators including life expectancy and causes of death, to assist with monitoring ‘Closing the Gap’ health targets. The method involves using data linkage to enhance the identification of Aboriginal and Torres Strait Islander people in death registrations. Current official mortality statistics for Indigenous Australians include only those 5 jurisdictions which are considered to have adequate levels of Indigenous identification in death registrations data. The EMD method allows for the production of national mortality estimates that include data from all jurisdictions, and which have been adjusted for under-identification.

Official life expectancy estimates for Indigenous Australians are produced every 5 years by the Australian Bureau of Statistics. The EMD method provides estimates that complement those of the ABS, as well as allowing estimates of Indigenous life expectancy to be made for the jurisdictions with small Indigenous populations, such as Victoria and South Australia, for which official life expectancy estimates are currently not available. It is expected that in the future, the method will enable separate life tables to be prepared also for Tasmania and the Australian Capital Territory.

The enhancement method employed in this study enables the Indigenous status recorded on death records to be compared across a wide range of independent and comparative data sets, thereby improving the prospect of deriving a consistent and more robust Indigenous status for all death records. Because both the registered death records and comparative data sets used in enhancing the Indigenous status of the death records are available on a yearly basis, the method is able to produce life tables for all jurisdictions on a yearly basis, if required.

In developing the EMD, the AIHW created a base mortality data set, the Mortality Extract Data Set, by validating extracts of death records from the National Death Index against extracts of death records from the National Mortality Database. The Mortality Extract Data Set was then linked to three independent comparative data sets: the National Hospital Morbidity Database, the Perinatal Data Collections of each jurisdiction and the national Residential Aged Care Database.

Analysis of the EMD shows that mortality – as assessed by measures such as the median age at death, age-specific death rates, the cumulative proportions of deaths occurring by specified ages, and age-standardised death rates – has declined for both Indigenous males and females nationally and in most jurisdictions.

Consistent with the observed decline in mortality, life expectancy at birth increased for both Indigenous males and females during the reference period (2001–2005 to 2011–2015). However, greater increases in life expectancy at birth occurred for non-Indigenous males and females, meaning that the gap in life expectancy between Indigenous and non-Indigenous Australians widened during the reference period.

Much of the gap in life expectancy between Indigenous and non-Indigenous Australians is due to the earlier age at death of Indigenous males and females. Deaths of Indigenous males aged under 45 contributed up to one-third (29%–36%) of the gap between Indigenous and non-Indigenous males, while deaths of Indigenous females aged under 45 contributed just over one-fifth (21%–22%) of the gap between Indigenous and non-Indigenous females.