A Longitudinal Approach to Estimating Life Expectancy for Aboriginal and Torres Strait Islander People and Non-Indigenous Australians

Australia’s Closing the Gap agreement includes a national target to close the life expectancy gap between First Nations and non-Indigenous Australians by 2031. Monitoring progress requires annual estimates for states and territories and smaller geographic areas, but existing official estimates are produced only around each 5-yearly Census, cannot support comparisons over time and are published for only 4 jurisdictions. We develop a longitudinal approach using linked Census, death registration and administrative data in the Person Level Integrated Data Asset (PLIDA). Supplementary administrative data improve population coverage, while infant mortality is estimated separately using perinatal and mortality collections. Indigenous status is assigned at entry to each study population and held constant during follow-up, ensuring consistent classification of deaths and person-years at risk. Bayesian hierarchical models are used to estimate mortality rates from sparse data by age, sex, Indigenous status, year and geography, with life expectancy derived using standard life-table methods and uncertainty quantified through the Bayesian framework.

Estimates from overlapping Census-based datasets are combined and adjusted to produce a consistent annual series from 2017 to 2023. Incorporating supplementary administrative data increases coverage of First Nations people from 74% to 97% of the Estimated Resident Population, substantially reducing potential selection bias. The framework supports annual estimates of life expectancy and gaps across all 8 states and territories, including through the COVID-19 period, and detailed cross-sectional analyses by remoteness within jurisdictions and socioeconomic disadvantage in 2022–2023. The longitudinal framework therefore provides new opportunities for monitoring Closing the Gap outcomes, assessing mortality trends over time and examining geographic and socioeconomic inequalities.

Presenters: AIHW project team, Oliver Bruhl (AGA) and Dr John Bryant

The project team is based in the First Nations Health and Welfare Group at the Australian Institute of Health and Welfare (AIHW), bringing together expertise in statistics, demography, data analysis, and First Nations health and welfare. The team’s work builds on AIHW’s long-standing program of First Nations mortality and life expectancy research, shaped over many years by the leadership, guidance and support of Fadwa Al-Yaman. This legacy includes the development of the Enhanced Mortality Database and its successor, the Enhanced Indigenous Mortality Data Collection (EIMDC), established to strengthen the evidence base for national efforts to close the gap in life expectancy.

Building on this foundation, the current team is developing new approaches to measuring and understanding life expectancy, drawing on linked data and longitudinal methods to support more consistent monitoring over time and across Australia. The work is undertaken in close collaboration with the Australian Government Actuary (AGA), with valuable contributions from external expert advisers. Together, the team combines deep institutional knowledge with statistical and methodological expertise to strengthen the evidence available for understanding inequalities in mortality and life expectancy between First Nations and non-Indigenous Australians.

Dr John Bryant is a demographer and data scientist, specialising in Bayesian analysis, applied demography, and statistical computing. He has worked at Statistics New Zealand, the New Zealand Treasury, and the Institute for Population and Social Research in Thailand. He has a PhD in Demography from the Australian National University.

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