Methods
Age-standardised percentages
- Age-standardised percentages enable comparisons to be made between populations that have different age structures. Direct standardisation, in which the age-specific rates are multiplied by a constant population, was used in this report for data reported by mother’s Indigenous status. This effectively removes the influence of the age structure on the summary rate. The report states where age-standardised percentages have been used.
- All age-standardised percentages in this report have used the June 2001 Australian female estimated resident population aged 15–44 years as the standard population.
- For more information on methods used to report NPDC data refer to: Australia’s mothers and babies – Methods.
Notes for analysis by sub-populations
Data for all NCMIs are presented by three geographic boundaries:
- state and territory of birth
- Primary Health Network (PHN) of mother's usual residence
- Statistical Area Level 3 (SA3) of mother's usual residence
and at the national level by:
- hospital annual number of births
- hospital sector
- mother’s Indigenous status
Some indicators are disaggregated by other data groupings where relevant.
Notes for each sub-population analysis are as follows:
State or territory of birth
Births in 'Other territories' are included within their closest state.
Mother's age at birth
Excludes mothers for whom age is missing or not stated.
Mother's Indigenous status
- First Nations women include those who identified as Aboriginal, Torres Strait Islander, or both Aboriginal and Torres Strait Islander origin. Non-Indigenous refers to women who have not identified as Aboriginal or Torres Strait Islander.
- Excludes mothers for whom Indigenous status is missing or not stated.
- Data were directly age-standardised using the June 2001 Australian female estimated resident population aged 15–44 years.
- Crude (non-age-standardised) percentages are also presented for this disaggregation.
Mother's smoking status during pregnancy
Excludes mothers for whom smoking status was not stated.
Hospital sector
Includes births that occurred in a hospital only.
Hospital’s annual number of births
Includes births that occurred in a hospital or birthing centre only.
Whether labour was established
Excludes records where onset of established labour is not stated.
Sex of baby
Excludes records where sex of baby is not stated or not assigned.
Whether an episiotomy was performed
- Data reported from 2004 to 2013, a combined laceration and episiotomy value could be recorded; from 2014 onwards, episiotomy could be recorded separately.
- Excludes records where episiotomy status is not stated.
Mother's country of birth
- Excludes records where mother's country of birth is not stated.
- Data were mapped to the major and minor groups of the ABS Standard Classification of Countries (SACC), 2016. ABS SACC supplementary codes provided were mapped to the appropriate major and minor grouping where possible.
Remoteness of mother’s usual residence
- Remoteness area was derived by applying the ABS Australian Statistical Geography Standard (ASGS) remoteness structure to area of mother’s usual residence. Between 2012 and 2016, the 2011 ASGS (Edition 1) was used. Between 2017 and 2021, and for WA, SA and NT in 2022, the 2016 ASGS (Edition 2) was used. In 2022, ASGS Edition 3 was used for all jurisdictions except WA, SA and NT.
- Excludes mothers whose state or territory of residence was ‘Non-Australian resident’, ‘Not stated’, or ‘Other Territories’.
- Results are available from 2012 onwards.
Disadvantage quintile of mother's usual residence
- Disadvantage quintile was derived by applying the ABS Socio-Economic Indexes for Areas Index of Relative Socio-economic Disadvantage (SEIFA IRSD) to area of mother’s usual residence. Between 2012 and 2016, the 2011 SEIFA IRSD was used. Between 2017 and 2021, and for WA, SA and NT in 2022, the 2016 SEIFA IRSD was used. In 2022, the 2021 SEIFA IRSD was used for all jurisdictions except WA, SA and NT.
- Excludes mothers whose state or territory of residence was ‘Non-Australian resident’, ‘Not stated’, or ‘Other Territories’.
- Results are available from 2012 onwards.
PHN of mother's usual residence
- PHN of mother's usual residence was derived by applying the PHN boundaries released by the Department of Health and Aged Care to mother’s area of usual residence.
- Between 2012 and 2016, the 2015 PHN boundaries were applied to the 2011 ABS ASGS (Edition 1) Statistical Area Level 2 (SA2) of usual residence, or postcode of usual residence for ACT from 2012–2015 and NT for 2012. Between 2017 and 2021, and for WA, SA and NT in 2022, the 2017 PHN boundaries were applied to SA2 of the ABS 2016 ASGS (Edition 2). In 2022, the 2017 PHN boundaries were applied to SA2 of the ASGS Edition 3 for all jurisdictions except WA, SA and NT.
- Excludes mothers whose state or territory of residence was ‘Non-Australian resident’, ‘Not stated’, or ‘Other Territories’.
- Results are available from 2012 onwards.
SA3 of mother's usual residence
- SA3 of mother's usual residence reported using ABS ASGS SA3, derived from ABS ASGS SA2. Until 2021, the 2016 ASGS (Edition 2) was used. In 2022, the ABS 2016 ASGS (Edition 2) was used in WA, SA and NT, and the ABS ASGS Edition 3 was used in all other jurisdictions.
- Excludes mothers whose state or territory of residence was ‘Non-Australian resident’ or ‘Not stated’.
- Results for SA3 of mother's usual residence reported using a 3-year aggregate, 2020–2022.