2037.0.55.001 - Microdata: Census of Population and Housing, Census Sample File, Expanded CURF, 2006 Quality Declaration 
Latest ISSUE Released at 11:30 AM (CANBERRA TIME) 13/05/2009   
   Page tools: Print Print Page Print all pages in this productPrint All RSS Feed RSS Bookmark and Share Search this Product
  • Quality Declaration

Institutional Environment

Confidentialised Unit Record Files (CURFs) are released in accordance with the conditions specified in the Statistics Determination section of the Census and Statistics Act 1905 (CSA). This ensures that confidentiality is maintained whilst enabling micro level data to be released. More information on the confidentiality practices associated with CURFs can be found at the "How is CURF data confidentialised?" page.

For information on the institutional environment of the Australian Bureau of Statistics (ABS), including the legislative obligations of the ABS, financing and governance arrangements, and mechanisms for scrutiny of ABS operations, please see ABS Institutional Environment.


The Census Sample File (CSF) is available as a basic 1% sample file and expanded 5% sample file. The difference between the basic and expanded files are detailed in the 2006 Census Sample File Technical Paper.

The level of detail provided for selected key data items are:

Basic CURFExpanded CURF
AgeSingle years 0-24, five year age group 25-84, top coded 85+Single years 0-84, top coded 85+
Indigenous StatusNot availableIndigenous, Non-indigenous, not stated
GeographyStatistical Regions, a number of regions are combinedStatistical Regions (2 regions combined)


The Census Sample File was originally known as the Household Sample File (HSF) and first released in 1981. Subsequent sample file releases have occurred every five years in accordance with the Census of Population and Housing. The next CSF release is expected to occur in 2013 based on the 2011 Census of Population and Housing.


The 1% Basic CSF contains the unit records of a 1 in 100 sample of occupied private dwellings along with the occupants of those dwellings and a 1 in 100 sample of people from Non-private dwellings along with the associated dwelling. The 5% Expanded CSF contains the unit records from a 1 in 20 sample of occupied private dwelling along with the occupants of those dwellings and a 1 in 20 sample of people from non-private dwellings along with the associated dwelling. Users should be aware of the effects of sampling error when extracting estimates from the CSF. For more information on sampling error in the CSF please see Appendix 2 of the Census Technical Manual.

Steps to confidentialise the data made available on the CURF are taken in such a way as to maximise the usefulness of the content while maintaining the confidentiality of respondents to ABS statistical collections. As a result, it may not be possible to exactly reconcile all the statistics produced from the CURF with published statistics.

The ABS aims to produce high quality data from the Census. To achieve this, extensive effort is put into Census form design, collection procedures and processing. There are four principle sources of error in Census data which quality management aims to reduce as much as possible; they are respondent error, processing error, partial or non-response and undercount. For more detail, see Census Data Quality.

While it is important for Census data to be comparable and compatible with previous Censuses, data must also remain relevant and topical to the needs of the community. Therefore there may be changes to classifications and topics between Census years. The changes between 2001 and 2006 Censuses are outlined in What's New for 2006 of the 2006 Census Dictionary.

Additionally, in order to meet confidentiality requirements, there may be changes in the amount of information made available in the sample file compared to previous files. These changes are summarised in Appendix 1 of the Census Sample File Technical Paper.

Users should note that previously the Census Sample File was known as the Household Sample File.


The 2006 Census Sample File Technical Paper is a key source for consultation when using a CURF. It includes survey objectives, methods and design; survey content; data quality and interpretation; output data items; and information about the availability of results; comparability with previous surveys; and the content of the CURF file.

The 2006 Census Dictionary contains definitions of data items used in the CSF and is a key source for data interpretation and availability of data beyond the limits of the sample files.

CURF notes for Accessibility

CURF microdata are not available to the public without special access being granted. All CURF users are required to read and abide by the Responsible Access to ABS Confidentialised Unit Record Files (CURFs) Training Manual. Application to access a particular CURF microdata can be completed and submitted for approval by following the steps listed in the How to apply for Microdata Frequently Asked Questions. A full list of available CURFs can be viewed via the Expected and available Microdata.

The Basic CURF can be accessed on CD-ROM, in addition to being accessed through the Remote Access Data Laboratory (RADL) and the ABS Data Laboratory (ABSDL). The Expanded CURF can only be accessed through RADL and ABSDL.
More detail regarding types and modes of access to CURFs can be found on CURF Access Modes and Levels of Detail web page.

If you have any questions regarding access to CURF Microdata please contact the Microdata Access Strategies Section at <microdata.access@abs.gov.au> or call 02) 6252 7714.