Age- and sex-specific estimated resident populations (ERPs) for NSW Statistical Areas (Levels 1 and 2) (SA1 and SA2) at 30 June were obtained from the Australian Bureau of Statistics (ABS) for use with calendar year data. Linear temporal interpolation was used to derive 31 December age- and sex-specific population estimates for use with financial year data. Populations of NSW Local Health Districts (LHDs) were derived by aggregating the appropriate SA1-level ERPs based on an SA1 to LHD concordance mapping. 

Population estimates match the year of health data. For example, the rate of NSW residents hospitalised in, for example, 2022-23 is calculated using the number of hospitalisations in 2022-23 and the estimate of residential population in NSW in the 2022-23 financial year. Further, the death rate of NSW residents in, for example, 2022 is calculated using the number of deaths in 2022 and the estimate of residential population in NSW in the 2022 calendar year.  

The 2001 Australian standard population was used for age-adjustment or standardisation of rates. For this report, the Australian estimated residential population (persons) as at 30 June 2001 was used as the standard population. The same population was used for males and females to allow valid comparison of age-standardised rates between the sexes. This standard population is determined by the Australian Institute of Health and Welfare and usually changed every 20 years. Currently, 30 June 2001 remains the standard population.

Age-adjustment of rates used direct age-standardisation. This method adjusts for effects of differences in the age composition of populations across time or geographic regions. The directly age-standardised rate is the weighted sum of age-specific (five-year age group) rates, where the weighting factor is the corresponding age-specific standard population. Please refer to the HealthStats PLUS Methods paper on Age standardisation.

The projections have been produced by the NSW Department of Planning, Housing and Infrastructure (DPHI). The projections result from assumptions about future trends in fertility, mortality and migration and incorporate information from DPHI, the ABS, the Commonwealth Department of Immigration and Border Control and the NSW Ministry of Health. The projections used in HealthStats NSW are based on the latest estimated resident population as published by the ABS linearly interpolated to the first projection year in the DPHI estimates following this time point.

The inter-census year projections to 2036 have been produced by the Centre for Epidemiology and Evidence by interpolating the census-year (2016, 2021, 2026, 2031 and 2036) projections provided by DPHI. These projections have been used to calculate rates in indicators showing projected deaths and hospitalisations in NSW.

The year-to-year projections of population to 2041 by 5-year age group for the whole of New South Wales and Local Health Districts are available from HealthStats NSW. 

References

NSW population, household and dwelling projections. NSW Department of Planning, Housing and Infrastructure. Available at: https://www.planning.nsw.gov.au/research-and-demography/population-projections