Recoding is the process of aggregating categories of a classification into groups. These groups may contain either the full basic classification, or only part of it. Each of the Census data variables disseminated has a basic classification. Output may be produced using this basic classification level, or using recodes.
Tables can be customised to individual requirements using recodes. For example, if data are required for school children only, a suitable recode for the variable Age (AGEP) may show the age groups 5-8 years; 9-12 years; 13-15 years; and 16-18 years, reducing the table to a more manageable size.
Recoding may also be necessary to meet the confidentiality requirements of the ABS, to prevent the identification of individual persons or organisations. For example, a table showing the full classification of Occupation cross-classified with the full classification of Country of Birth of Person (BPLP) at Statistical Local Area (SLA) level, would contain many very small cells. These cells would then be randomly adjusted to prevent the release of confidential data. By reducing the classificatory or geographic detail, the table would be less affected by introduced random error.
Many recodes have already been designed and incorporated as standards, based on demand from previous censuses and are included in Census output products. The design and implementation of non-standard recodes for individual requirements is done by ABS Information Consultancy (contact details for Information Consultancy are provided on the back cover of this publication). The ABS encourages clients to use standard ABS recodes to allow meaningful comparison of data.
See also Classifications, Confidentiality, Section 1 - 2006 Census Classifications, Information Consultancy, Introduced random error, Mnemonics, Variables.