Technical notes

Activity data

NBCSP

Invites issued are a count of all screening invitations issued by the NBCSP register within the relevant 3-month period for those within the target age group. Two-yearly screening was only fully rolled out from 1 January 2019, and prior to that specific ages invited within the 50–74 were invited to screen each year. This phasing in of age groups is also reflected in quarterly activity counts. The age groups invited for the periods covered in this report are shown in the section NBCSP age groups invited by year.

Total kits returned are a count of all kits returned during the relevant 3-month period. This can include kits issued in a previous period and returned to the register at a later date. It can also include multiple kits per person (invitee) within a 3-month period due to expired, spoiled, damaged, or incorrectly completed kits. 

Although terminology is similar, activity counts of invites issued or screening kits returned should not be directly compared with the formal NBCSP participation indicator. Activity counts are a count of events, not people.

NBCSP quarterly activity data in this report includes data between 1 January 2014 and 30 September 2019.

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 participation rates by state or territory are age-standardised for the target age group for BreastScreen Australia (50–69 and 50–74) and the National Cervical Screening Program (25–74). All other rates within this report (including national rates reported for a single reporting period) are age-specific (crude) rates.

Geography

Participation rates in the NBCSP, BreastScreen Australia 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.

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

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

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.

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, 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. 

Note that NCSP participation data by PHN and SA3 are not available at this time.

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 the NBCSP register data 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 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 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.

NBCSP age groups invited by year 

Two-yearly screening was only fully rolled out from 1 January, 2019. The specific ages invited within the 50–74 age for the periods covered in this report are shown in the following table:

NBCSP ages invited by year

Phase

Start date

End date

Ages invited

1

7 August 2006

30 June 2008

55 and 65

2

1 July 2008

30 June 2011(a)

50, 55 and 65

2(b)

1 July 2011

30 June 2013

50, 55 and 65

3

1 July 2013

Ongoing

50, 55, 60 and 65

4

1 January 2015

31 December 2015

50, 55, 60, 65, 70 and 74

4

1 January 2016

31 December 2016

50, 55, 60, 64, 65, 70, 72 and 74

4

1 January 2017

31 December 2017

50, 54, 55, 58, 60, 64, 68, 70, 72 and 74

4

1 January 2018

31 December 2018

50, 54, 58, 60, 62, 64, 66, 68, 70, 72 and 74

4

1 January 2019

31 December 2019

50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72 and 74

(a) Eligible birth dates, and thus invitations, ended on 31 December 2010.

(b) Ongoing NBCSP funding commenced.

Note: The eligible population for all Phase 2 and 3 start dates incorporate all those turning the target ages from 1 January of that year onwards.

Participation rates

NBCSP

Participation rates represent the percentage of people invited to screen through the NBCSP during the relevant 2-year period, who returned a completed screening test within that period or by 30 June of the following year. The number of individuals invited to screen excludes those who deferred or opted out without completing their screening test. As two-yearly screening was only fully rolled out from 1 January 2019, the specific ages invited within the 50–74 age group for the periods covered in this report are shown in the section NBCSP age groups invited by year.

NBCSP data in this report covers the period 1 January 2014 to 31 December 2018 for participation.

The number of people who have participated since the NBCSP commenced in 2006 includes every individual invited to screen in the program at least once between 7 August 2006 and 31 December 2018, who returned at least one completed screening test by 30 June 2019.

BreastScreen Australia

Participation rates represent the percentage of women in the population aged 50–74 screened by BreastScreen Australia over 2 calendar years. The population denominator was the average of ABS Estimated Resident Population (ERP) for females aged 50–74 within the relevant geographical area (PHN, SA3) for the relevant 2-year reporting period.

BreastScreen Australia changed its target age group from 50–69 years to 50–74 years from July 2013; participation is reported for both the previous and current target age groups to allow comparison of trends with previously reported data. BreastScreen Australia data in this report covers the period 1 January 2014 to 31 December 2018.

NCSP

Participation in the NCSP for this report used a preliminary methodology to calculate participation until 5 years of data are available to calculate 5-year participation.  This was defined as the percentage of women in the population aged 25–74 who had at least one Cervical Screening Test in the single year 2018. Participation rates were calculated using the ABS Estimated Resident Population (ERP) for females aged 25–74 in 2018 ,adjusted to exclude the estimated proportion of women who have had a hysterectomy and COMPASS participants, and divided by 2.

For the first report for the new NCSP including data from the National Cancer Screening Register see the AIHW report National Cervical Screening Program Monitoring report 2019.

State or territory

For the NBCSP, state or territory reported refers to the state or territory of residence. For BreastScreen Australia and the NCSP, state or territory reported refers to the state or territory in which screening occurred, not the state or territory of residence.

Data sources

AIHW analysis of National Bowel Cancer Screening Program register data, state and territory BreastScreen Australia register data and state and territory cervical screening register data.

References

Australian Bureau of Statistics (ABS) 2010a. Australian Statistical Geography Standard (ASGS): Volume 1 — Main Structure and Greater Capital City Statistical Areas, July 2011. ABS cat. no. 1270.0.55.001. Canberra: ABS.

ABS 2010b. Australian Statistical Geography Standard (ASGS): Volume 3 — Non ABS Structures, July 2016. ABS cat. no. 1270.0.55.003. Canberra: ABS.

ABS 2016a. Australian Statistical Geography Standard (ASGS): Volume 1— Main Structure and Greater Capital City Statistical Areas, July 2016. ABS cat. no. 1270.0.55.001. Canberra: ABS.

ABS 2016b. Australian Statistical Geography Standard (ASGS): Volume 3 — Non ABS Structures, July 2016. ABS cat. no. 1270.0.55.003. Canberra: ABS.

Department of Health 2018. Primary Health Networks (PHNs). Canberra: Department of Health. Viewed 17 December 2018.