Methods

Data sources

This report uses data from:

  • the National Cancer Screening Register for bowel and cervical screening data
  • the National Bowel Cancer Screening Register, for participation data for reporting periods prior to 2018–2019
  • state and territory cervical screening registers, for participation data for reporting periods prior to 2018
  • state and territory BreastScreen Australia registers.

Data updates

Data in this report are sourced from live databases, which are updated over time, with later data supply likely to have a greater level of completeness. Data in this report may differ from other AIHW cancer screening reports, which are sourced at a different time.

Activity data for cervical and bowel cancer screening are updated each quarter.

Preliminary participation data for cervical, breast and bowel cancer screening are published ahead of the respective AIHW annual monitoring report for each program to give key stakeholders and policy-makers early access to these important data. As more recent data are used to update participation when the respective AIHW annual monitoring reports are released, preliminary participation data are subject to change.

Age-specific rates

The number of cases occurring in each specified age group divided by the corresponding population in the same age group. For example, in this report age-specific participation rates are calculated as the number of people participating in a screening program, divided by the number of people eligible to participate (or the number of people in the population of that age), expressed as a percentage.

Age-standardised rates

Age-standardisation is a way to remove the influence of age when comparing populations with different age structures (or relative number of people in each age group in a population). This is usually necessary because the rates of many diseases vary strongly (usually increasing) with age. The age structures of the different populations are converted to the same ‘standard’ structure, and then the disease rates that would have occurred with that structure are calculated and compared.

In this report, all rates reported (including national rates reported for a single reporting period) are age-specific (crude) rates, unless otherwise stated. Age-standardised participation rates for the target age group for BreastScreen Australia (50–69 and 50–74) and the National Cervical Screening Program (25–74) are available in the accompanying data tables, to allow comparisons to be made over time and across population groups.

Age-standardised participation rates are not available for the National Bowel Cancer Screening program, since only specific age groups were invited until the program was fully rolled out in 2020. For more information about the age groups invited in different years, see the section in the technical notes, ‘National Bowel Cancer Screening Program age groups invited by year’.

Geography

Participation rates in BreastScreen Australia, the NBCSP and the NCSP are presented for the following geographies:

  • Primary Health Network (PHN) areas: 31 areas covering Australia, defined by the Department of Health (Department of Health 2018).
  • Statistical Areas Level 3 (SA3s): 333 areas covering Australia.

Participation rates in the NBCSP are also presented for Statistical Areas Level 2 (SA2s): 2,196 areas covering Australia (for periods up to 2017–2018). SA2 data for the NBCSP were not available for 2018–2019 at the time of preparation of this report.

Both SA3s and SA2 are defined by the ABS within the Australian Statistical Geography Standard (ASGS):

  • The 2011 ASGS was used for the 2014–2015 to 2017–2018 NBCSP data, and 2014–2015 and 2015–2016 BreastScreen Australia data in this report.
  • The 2016 ASGS was used for the NCSP, 2016–2017 and later BreastScreen Australia data, and 2018–2019 and later NBCSP data in this report.

For BreastScreen Australia and the NCSP, population denominators for the PHN geographical areas were derived using ABS Estimated Resident Population (ERP) data by postal areas (ABS 2020) and the PHN correspondence file. These data were classified according to the PHN 2017 structure (ABS 2016).

Participation data for some SA3s across the three screening programs were not published due to reliability concerns arising from low numbers in these regions and/or due to poor correspondence (as determined by the Australian Bureau of Statistics).

Assigning geography

For NBCSP invitees, geographic areas (PHN areas, SA3s and SA2s) were assigned using Statistical Area Level 1 (SA1) of usual residence. For invitees without reliable SA1 details geographic areas were assigned using postcode of usual residence. As some postcodes cross the boundaries of PHNs, SA3s or SA2s the use of postcode correspondences may lead to some minor inaccuracies in results. For the 2018–2019 reporting period, participation by PHN and SA3 geographical areas were reported and assigned using postcode of usual residence.

Where SA1 codes and postcodes could not be attributed to a PHN, SA3 or SA2, these invitees were included in an 'Unknown' group in the data tables, and are excluded from data visualisations.

For BreastScreen Australia and the NCSP, PHN areas and SA3s were assigned using postcode of usual residence. Where postcodes could not be attributed to a PHN or SA3, these women were included in an 'Unknown' group, where possible in the data tables, and were excluded from data visualisations. For analyses where a postcode or SA1 boundary overlapped PHN areas, SA3 or SA2 boundaries, the relevant records were attributed based on the percentage of the population within that postcode or SA1 that fell within the PHN area SA3, or SA2.

Participation by geographic areas represents the geographic data available within the relevant data source at the time of first publication, and are not retrospectively updated. This is particularly of relevance to NCSR data for the NBCSP as some improvements to geographical information may be made over time.

Correspondences

Correspondence files for PHN were sourced from the Australian Statistical Geography Standard (ASGS): Volume 3 - Non ABS Structures (ABS 2010b, 2016b). For the NBCSP up to and including 2017–2018 and BreastScreen Australia data for 2014–2015 and 2015–2016, data were classified according to the PHN 2015 structure (ABS 2011). BreastScreen Australia 2016–2017 and later data, NSCP data and NBCSP data from 2018–2019 onwards were classified according to the PHN 2017 structure (ABS 2016). PHNs were established in June 2015, and some of the geographic information presented includes data before that date. For further details on PHNs see the Department of Health’s website.

For the NBCSP and BreastScreen Australia data for 2014–2015 and 2015–2016, correspondence files for SA3s and SA2s were sourced from Australian Statistical Geography Standard (ASGS) 2011: Volume 1 (ABS 2010a). For 2016–2017 onwards BreastScreen Australia data correspondence files for SA3s were sourced from Australian Statistical Geography Standard (ASGS) 2016: Volume 1 (ABS 2016a).

The correspondences produced by the ABS can be found on data.gov.au by searching for: ‘ASGS’, the 'year', and ‘correspondences’.

The number of people in different geographic areas (PHNs, SA3s or SA2s) may not sum to 'Australia' total due to rounding. The Australia total also includes some records that could not be attributed to a geographic area.

SA3s and SA2s with a numerator less than 20 or a denominator less than 100 were suppressed.

For a full list of AIHW products that include data and results by small areas (for example, by Primary Health Network areas) see AIHW data by geography.