About the methods
The population (denominator for rates) as of 30 June at the beginning of the financial year (for instance, 30 June 2017 for the period 2017–18) are derived from the Australian Bureau of Statistics’ (ABS) Regional population by age and sex, 2023 (ABS 2024). Population estimates from 2017 to 2021 are based on the final version, while population estimates for 2022 are based on the revised version. Revised versions are subject to further revision by the ABS.
Age-standardised rates are hypothetical rates that would have been observed if the populations studied had the same age distribution as the standard population. This facilitates comparisons between populations with different age structures and changes over time within an area. This adjustment is important because the prevalence of health conditions and rates of health service use vary with age.
The direct method of age-standardisation was applied to the data. Age-standardised rates were derived by calculating crude rates by five-year age groups of 0–4 to 85+ years. These rates were then given a weight that reflected the age composition of the standard population (ABS estimated resident population for Australia as of 30 June 2001). If a patient’s age was recorded as ‘unknown’, their records were excluded from the age-standardised rates.
ABS (2024) Regional population by age and sex, 2023, ABS, Australian Government, accessed 16 July 2025.