2085.0 - Microdata: Australian Census Longitudinal Dataset with Social Security and Related Information, experimental statistics, 2006-2011 Quality Declaration 
Latest ISSUE Released at 11:30 AM (CANBERRA TIME) 23/08/2017  First Issue
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INSTITUTIONAL ENVIRONMENT
RELEVANCE
TIMELINESS
ACCURACY
COHERENCE
INTERPRETABILITY
ACCESSIBILITY


INSTITUTIONAL ENVIRONMENT

The Australian Census Longitudinal Dataset with Social Security and Related Information (ACLD-SSRI) is released in TableBuilder and as a microdata product in DataLab. Microdata files are released in accordance with the conditions specified in the Statistics Determination section of the Census and Statistics Act 1905. This ensures that confidentiality is maintained whilst enabling micro level data to be released. More information on the confidentiality practices associated with TableBuilder, User Guide (cat. no. 1406.0.55.005) can be found on the Confidentiality page. To protect confidentiality of data within DataLab, users are supervised at all times and must not bring mobile phones, cameras, USB keys, laptops, palm pilots or similar transmission or storage devices into the secure location. All outputs produced by users in DataLab are manually cleared for release after the session.

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, see ABS Institutional Environment.

In April 2012, the ABS became an accredited Integrating Authority under the Commonwealth data integration interim arrangements. A copy of the accreditation claims made by the ABS, which have been verified by an independent auditor, is available through the National Statistical Service (NSS) website. The ABS only undertakes data integration for statistical and research purposes and where there is a strong public benefit in doing so.


RELEVANCE

Data for the Census of Population and Housing used in this product were collected on 8 August 2006 and 9 August 2011. The scope of the Census is all persons in Australia on Census night excluding certain diplomatic personnel of overseas governments. In addition persons who were overseas visitors on Census Night were excluded from the scope of the 2006 ACLD sample.

The Census collects information on demographics, income, labour force, unpaid work, dwelling characteristics and family and household relationships.

For more information, see How Australia Takes a Census, 2011 (cat. no. 2903.0).

Settlement Database (SDB) data contains information on persons who had a permanent visa with a date of arrival between 1 January 2000 and 9 August 2011 (inclusive). The SDB date of arrival on which the scope is based reflects an individual's latest arrival pertaining to their latest permanent visa. For an offshore applicant, the SDB arrival date is when the applicant arrives in Australia on that permanent visa. However, for a person who applies onshore for a permanent visa, the date of arrival listed on the SDB is the date of their last entry into Australia.

SSRI data contains information on persons receiving selected Australian Government benefits as of the end of September 2011. It includes those persons who were on suspended benefits at this time, as well as their partner information where available.

For further information, particularly regarding analysis limitations of the ACLD-SSRI records with both migrants and SSRI information, refer to Scope and Coverage in the Methodology section.


TIMELINESS

The Census of Population and Housing is conducted every five years. For further information see the publication How Australia Takes a Census, 2011 (cat. no. 2903.0).

The first wave of Census data for the ACLD was from 2006 and the second from 2011. SDB data covers visa holders whose last arrival was made between 1 January 2000 and 9 August 2011 (inclusive) and SSRI data was from September 2011.


ACCURACY

The ACLD was created using data linkage techniques without name and address but with other characteristics from the Census. It was based on a 5% random sample from the 2006 Census (979,661 records) of which 82% (800,759) were linked to a 2011 Census record. The false link rate is estimated at around 5–10%. In the linkage of 2011 Census records to SDB records, a 76% linkage rate was achieved, see Microdata: Australian Census and Migrants Integrated Dataset, 2011 (cat.no. 3417.0.55.001). In the linkage of ACLD 2011 Census records to SSRI records, as the overlap of these two datasets is unknown, it is difficult to calculate an exact linkage rate for this exercise, see Linking Methodology in Methodology section of this publication.

Sampling error occurs because only a small proportion of the total population is used to produce estimates that represent the whole population. Sampling error refers to the fact that for a given sample size, each sample will produce different results, which will usually not be equal to the population value. There are two common ways of reducing sampling error - increasing sample size and utilising an appropriate selection method (for example, multi-stage sampling would be appropriate for household surveys). Given the large sample size for the ACLD (1 in 20 persons), and simple random selection, sampling error is minimal.

The ACLD sample was weighted to an estimate of the population that was resident in Australia at the time of both the 2006 and 2011 Censuses. The weights adjust for missed links and Census undercount.

Information on methodology, linkage quality and weighting can be found in Information Paper: Australian Census Longitudinal Dataset - Methodology and Quality Assessment, 2006 and 2011 (cat. no. 2080.5). Information on the weighting of the ACLD has since changed with the update of the ACLD file that was released on 11 February, 2016. For information on the current weighting please see the Methodology section of this publication.

The ACLD weights are not benchmarked to the SDB or SSRI populations, so weighted estimates for SDB and SSRI populations should be interpreted with caution.

Steps are taken to confidentialise the data made available on TableBuilder in such a way as to maximise the usefulness of the content while maintaining the confidentiality of respondents selected in the ACLD sample. As a result it may not be possible to exactly reconcile all the statistics produced from the microdata with other published statistics. Further information about the steps taken to confidentialise the microdata can be found in TableBuilder confidentiality.

Estimates of migrants in the ACLD-SSRI using the SDB information may differ from the estimates produced in the ACMID for several reasons:

    • the ACLD-SSRI is a 5% random sample from the 2006 Census population, not the 2011 Census population;
    • more recent migrants, that is, those that arrived between the 2006 and 2011 Censuses, are not included in the sample;
    • linked records in the ACLD-SSRI were benchmarked to an estimate of the population that was resident in Australia at the time of both the 2006 and 2011 Censuses;
    • the SDB information was merged to the 2011 Census records of people that were able to be linked (and not all records were able to be linked).

Due to these reasons above and other quality issues in the ACLD, estimates of migrants using the SDB information should generally be treated with caution.


COHERENCE

A small percentage of linked records have inconsistent data, such as a different country of birth at the two time points or an age inconsistency of more than one year. Inconsistencies may be due to:
    • false link - the record pair does not belong to the same individual
    • reporting error - information for the same individual was reported differently in 2006 and 2011
    • processing error - the value of a data item was inaccurately assigned or imputed during processing. ACLD-SSRI microdata contains a large number of data items and in some cases the level of detail has been collapsed from that described in the Census Dictionary. For more information on the level of detail provided, please see the associated data item list.

While the 2006 and 2011 Censuses had predominantly the same questions and were processed in a similar way, there were some differences between them.

Notable data items that are different between Census years are personal, family and household income. Income was collected in ranges and these ranges are different in different Census years. The ACLD does not include an adjustment to income data for inflation.

Some data items were derived differently between Censuses. To aid comparability, the 2006 variable was re-derived to make it consistent with the 2011 derivation.

2006 Geography was originally disseminated according to the Australian Statistical Geography Classification. There were significant changes in the geographical classification used in the Census between 2006 and 2011 with the introduction of the Australian Statistical Geographic Standard. In order to facilitate comparison, a 'best fit' of 2006 collection districts to align with the 2011 geographic boundaries was created, however in some cases this will be an approximation only.

The exception is Remoteness Areas where no adjustment was made and 2006 boundaries and definitions were applied for usual address for that time period.

For more information on the differences between the 2006 and 2011 Census see What's new for 2011.


INTERPRETABILITY

This publication should be referred to when using the microdata. It contains information on the Sample Methodology, File Structure, Using the ACLD-SSRI in TableBuilder, The ACLD-SSRI in DataLab, Conditions of use and the Data items list.

Weights on the ACLD-SSRI attempt to account for missed links and Census undercount between the 2006 and 2011 Censuses. Weights do not attempt to account for missed links between the ACLD and either the migrant-related information or the social security information. Estimates and proportions of these groups will therefore be underestimates.

Detailed information on methodology, linkage quality and weighting can be found in Information Paper: Australian Census Longitudinal Dataset - Methodology and Quality Assessment, 2006 and 2011 (cat. no. 2080.5). Information on the weighting of the ACLD has since changed with the update of the ACLD file that was released on 11 February, 2016. For information on the current weighting please see the Methodology section of this publication.

The ABS publishes extensive information on Census Data Quality.


ACCESSIBILITY

ACLD-SSRI can be accessed through TableBuilder and DataLab.

This microdata product is available to approved users. Users wishing to access the microdata should read the How to apply for Microdata web page, before applying for access through the Registration Centre. Users should also familiarise themselves with information available via the Microdata web pages.

Any questions regarding access to microdata can be forwarded to microdata.access@abs.gov.au or phone (02) 6252 7714.