Exploring a Triple System Estimator to Support Official Population Estimation

James Chipperfield, Australian Bureau of Statistics
Peta Darby, Australian Bureau of Statistics
Claire Clarke, Australian Bureau of Statistics
John Power, Australian Bureau of Statistics

The Australian Bureau of Statistics (ABS) is exploring how linked administrative data could be used to enhance population estimates. Currently the ABS uses the Census and Post Enumeration Survey (PES) as part of a dual capture approach. While this approach currently performs well, the increased challenges in achieving high response rates and increased demand for small-area population estimates means alternative approaches should be explored. The ABS has undertaken initial research exploring a triple system estimator (TSE) that links three key data sources: Census, Post Enumeration Survey (PES) and administrative data (the Person Level Integrated Data Asset, PLIDA). Initial results show that the TSE produced population estimates within the 95% confidence interval of the published population estimate for seven out of eight states/territories when stratified by age group and state/territory. When the stratification included Indigenous status, the TSE produced population estimates within the 95% confidence interval of the published estimate for four out of eight states/territories. Further work is planned on testing the impact of TSE utilization on population estimates throughout the 2026 Census and PES cycle, and on the feasibility of implementation thereafter.

Keywords: Population projections, forecasts, and estimations, Linked data sets , Census data, Data and Methods

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