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National Healthcare Agreement: PI 11-Cervical screening rates, 2012 QS

Identifying and definitional attributes

Metadata item type:Help on this termQuality Statement
METeOR identifier:Help on this term500681
Registration status:Help on this termHealth, Retired 14/01/2015

Relational attributes

Indicators linked to this Quality statement:Help on this term

National Healthcare Agreement: PI 11-Cervical screening rates, 2012 Health, Retired 25/06/2013

Data quality

Quality statement summary:Help on this term
  • Remoteness and socioeconomic status are based on postcode of residential address at the time of screening, not the location of screening. State/territory disaggregation by remoteness and socioeconomic status is subject to data quality considerations.
  • Hysterectomy fractions are derived from the Australian Institute of Health and Welfare (AIHW) National Hospitals Morbidity Database.
  • Indigenous status is not collected by cervical cytology registers.
Institutional environment:Help on this term

The National Cervical Screening Program (NCSP) is a joint program of the Australian Government and State and Territory governments. The target age group is women aged 20–69 years.

Cervical cytology registers in each State and Territory are maintained by jurisdictional Program managers. Data are supplied for inclusion on registers by pathology laboratories. Data from cervical cytology registers are provided to the AIHW annually in an aggregated format.

The NCSP is monitored annually. Results are compiled and reported at the national level by the AIHW in an annual Cervical screening in Australia report.

Timeliness:Help on this term

Data available for the 2012 COAG Reform Council report are based on the two-year calendar period 1 January 2009 to 31 December 2010. Data are presented as a rate for the two-year period to reflect the recommended screening interval.

Accessibility:Help on this term

The NCSP annual reports are available via the AIHW website where they can be downloaded free of charge.

Interpretability:Help on this termWhile numbers of women screened are easy to interpret, calculation of age-standardised rates with allowance for the proportion of the population who have had a hysterectomy is more complex and the concept may be confusing to some users. Information on how and why age-standardised rates have been calculated and how to interpret them as well as the hysterectomy fraction is available in all AIHW NCSP monitoring reports, for example, Cervical screening in Australia 2008-2009.
Relevance:Help on this term

The data used to calculate this indicator are accurate and of high quality. The cervical cytology registers collect information on all Pap tests undertaken in Australia except where women advise the clinician they do not wish to have their data collected. The use of ERP based on Census data for denominators provide the most comprehensive data coverage possible. The data are entirely appropriate for this indicator.

For participation nationally, the numerator is the number of women aged 20–69 years screened in each State and Territory in 2009 and 2010, supplied as aggregated data, with the level of aggregation being at postcode level, by each State and Territory. The denominator is the average of the 2009 and 2010 Australian Bureau of Statistics (ABS) Estimated Resident Population (ERP) for women aged 20–69 years, adjusted to exclude the estimated number of women who have had a hysterectomy, using national hysterectomy fractions.

Caution is required when examining differences across states and territories of Australia due to the substantial differences in population, area, geographic structure, policies and other factors.

For participation by remoteness and socioeconomic status, the numerator is the number of women screened in 2009 and 2010 aged 20–69 years who reside in each of the remoteness and socioeconomic status categories. A postal area (POA) to remoteness concordance and a POA to socioeconomic status concordance were used to allocate women screened to remoteness and socioeconomic status categories based on their postcode. Aggregated postcode data are supplied from each State and Territory, and summed to generate the number of women screened by remoteness and socioeconomic status at the national level. The denominator is the average of the 2009 and 2010 ABS ERP for women aged 20–69 years in each remoteness and socioeconomic status category, generated by applying a POA to remoteness concordance and a POA to socioeconomic status concordance to POA ERP, adjusted to exclude the estimated number of women who have had a hysterectomy, using national hysterectomy fractions.

Caution is required when examining differences across remoteness and socioeconomic status categories for several reasons. First, while the postcode of women screened is interpreted as postcode of residence, some women may supply an address other than where they reside, or their postcode may be invalid or missing. Second, because the concordances are based on the 2006 Census, the accuracy of both Australian Standard Geographical Classification (ASGC) and Socio-Economic Index for Areas (SEIFA) Index of Relative Socio-economic Disadvantage (IRSD) diminishes due to subsequent changes in demographics within some postcode boundaries, and some boundaries themselves may have changed over time. Third, many valid postcodes are omitted from the socioeconomic status concordance in particular, meaning that many screened women are unable to be allocated to a socioeconomic status category (the remoteness concordance contains a more comprehensive list of postcodes, but some women will still be missed).

Breakdown of remoteness and socioeconomic status categories by State and Territory introduces an additional source of inaccuracy because of the potential for some women to be allocated to a state or territory different to the one in which they reside. State and territory totals for South Australia, Western Australia and the Northern Territory are affected by cross-border issues that make it impossible to allocate State or Territory of residence with absolute accuracy. Therefore rates for these jurisdictions should be treated as estimates only.

Accuracy:Help on this term

This indicator is calculated on data that have been supplied to the AIHW by individual State and Territory registries. Prior to publication, the results of analyses are referred back to states and territories for checking and clearance. Any errors found by states and territories are corrected once confirmed. Thus participation by State and Territory, based on the state or territory in which the woman was screened, is both robust and readily verified.

However, States and Territories are unable to check or verify participation by State and Territory of residence.

States and Territories are also unable to check or verify participation by remoteness or participation by socioeconomic status, since their data, once supplied to the AIHW, are nationalised and thereby lose their state or territory identity.

The allocation of women screened to a remoteness area and socioeconomic status by their postcode introduces a level of inaccuracy

Postcode does not always provide adequate information to establish State or Territory of residence. Due to issues with cross-boundary postcodes, and beyond the control of the State and Territory cervical cytology registers involved, participation rates in South Australia, Western Australia and the Northern Territory could not be accurately calculated, and should therefore be treated as estimates with the potential for significant levels of error. Issues with cross-boundary postcodes also means that participation in Remote and Very remote areas in South Australia and the Northern Territory are particularly difficult to estimate, and as such have the potential for greater levels of error than other remoteness areas.

Concordances to allocate women screened to a remoteness area and socioeconomic status by their postcode are based on 2006 boundaries and classifications, while the current data for this indicator are for 2009-2010. Overall, many postcodes may not have valid POA-based socioeconomic status or remoteness data available, and many may have changed classification group since 2006 and be giving inaccurate information now.

Further, there may not be a postcode for all women screened, or the postcode supplied may not be valid. For those women that do have a valid postcode, many cannot be allocated to a remoteness or socioeconomic category, as their postcode may not be included in the concordances — this is a greater issue for socioeconomic status, since this concordance contains fewer postcodes than does the remoteness concordance. Further, this may affect some remoteness and socioeconomic categories more than others.

The number of women screened in 2009–2010 that are unable to be allocated to a category are as follows (based on state or territory of postcode):

Remoteness: 1,138 women excluded (NSW: 97 excluded; Vic: 564 excluded; Qld: 256 excluded; WA: 2 excluded; SA: 8 excluded; Tas: 11 excluded; ACT: 11 excluded; NT: 189 excluded).

Socioeconomic status: 25,414 women excluded (NSW: 3,200 excluded; Vic: 3,992 excluded; Qld: 1,223 excluded; WA: 7,285 excluded; SA: 521 excluded; Tas: 203 excluded; ACT: 457 excluded; NT: 8,533 excluded).

No adjustments have been made to account for excluded women in the data.

Women residing in postcodes that cross boundaries are allocated to the state or territory according to ABS classifications. Women are counted only once in the two-year period 1 January 2009 to 31 December 2010, even if they were screened more than once during this period. All women screened in each State and Territory are included in order to present the most accurate national picture of cervical screening. This may lead to a small amount of double-counting, since one woman could be screened, and therefore counted, in two different jurisdictions over this two-year period, or a woman’s screening record may appear on two cervical cytology registers.

Women who opt off the cervical cytology register are not included in the participation data, but this is thought to only exclude around 1 per cent of all women screened.

Cell suppression was required for some data due to denominators less than 1,000 or due to rates that were unable to be sensibly estimated.

The Estimated Resident Population data are provided by the ABS.

Coherence:Help on this term

Some of these data are published annually in Program monitoring reports prepared by the AIHW. These reports include participation by State and Territory and participation by remoteness and socioeconomic status categories nationally. Data for 2009–2010 will be published in 2012.

State and Territory participation will differ between these data and those published in Cervical screening in Australia 2009–2010, because State and Territory participation in cervical screening monitoring reports is based on State or Territory of screen, rather than State or Territory of residence, since this is more appropriate for program monitoring. However, participation by remoteness areas and socioeconomic status categories nationally will be the same.

Relational attributes

Related metadata references:Help on this term

Supersedes National Healthcare Agreement: PI 11-Cervical screening rates, 2011 QS Health, Superseded 04/12/2012

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