In accordance with the Census and Statistics Act 1905, data in TableBuilder are subjected to a confidentiality process before release. This confidentiality process is applied to avoid releasing information that may lead to the identification of individuals, families, households, dwellings or businesses, without impairing the usefulness of the tables.
Care should be taken in analysing tables with cells containing small numbers. No reliance should be placed on small number cells or cells with large percentage Relative Standard Error (RSE) values. Aside from the effects of the confidentiality process, sampling error and possible respondent and processing errors have the greatest relative impact on small numbers and cells with large percentage RSEs.
A technique has been developed to randomly adjust cell values. Random adjustment of the data is considered to be the most satisfactory technique for avoiding the release of identifiable data in Survey TableBuilder. When the technique is applied, all cells are adjusted to prevent any identifiable data being exposed. These adjustments result in introduced random errors, however, the information value of the table as a whole is not impaired.
The totals and subtotals in tables are also subjected to small adjustments. These adjustments of totals and subtotals include modifications to preserve the additivity within tables. Although each table of this kind is internally consistent, comparisons between tables which contain similar data may show some minor discrepancies. In addition the tables at different geographic levels are adjusted independently and tables at the higher geographic level may not be equal to the sum of the tables for the component geographic units.
It is not possible to determine which individual figures have been affected by random error adjustments, but the small variance which may be associated with derived totals can, for the most part, be ignored.
Some RSE values may also be adjusted, to ensure consistency with the cell values.
This page last updated 5 December 2012