In accordance with the Census and Statistics Act 1905, all data in TableBuilder are subjected to a confidentiality process before release. This confidentiality process is undertaken to avoid releasing information that may allow the identification of particular individuals, families, households, dwellings or businesses.
Steps to confidentialise microdata are taken in such a way as to maximise the usefulness of the content while maintaining the confidentiality of respondents. 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 is available here: TableBuilder, User Guide: Confidentiality (cat no. 1406.0.55.005).
Processes used in TableBuilder to confidentialise records include the following:
- perturbation of data, and
- field exclusion rules.
To minimise the risk of identifying individuals in aggregate statistics, a technique is used to randomly adjust cell values. This technique is called perturbation. Perturbation involves small adjustments of the statistics and is considered the most satisfactory technique for avoiding the release of identifiable statistics while maximising the range of information that can be released. These adjustments have a negligible impact on the underlying pattern of the statistics.
The introduction of these adjustments result in tables not adding up. As a result, randomly adjusted individual cells will be consistent across tables, but the totals in any table will not be the sum of the individual cell values. The size of the difference between summed cells and the relevant total will generally be very small.
Please be aware that the effects of perturbing the data may result in components being larger than their totals. This includes determining proportions.
System restrictions have been implemented which prevent the cross-tabulation of certain data items within the following 2016 Census Pro datasets:
- 2016 Census - Counting Persons, Place of Enumeration
- 2016 Census - Counting Families, Place of Enumeration
- 2016 Census - Counting Persons, Estimating Homelessness
These restrictions have been applied to:
- maintain the confidentiality of respondents
- ensure the output of quality data
- assist users by not allowing combinations of data items that statistically should not be combined.
When the restriction is triggered the following error message will be displayed: "These variables cannot be used together". Other similar data items may be available. For example, if you are using Geographical Areas from Mesh Block (MBs), you may be able to use another Geographical Area data item instead, such as Main Statistical Area Structure (Main ASGS).