WHAT IS A CLASSIFICATION?
The Census gathers information on a number of topics about persons, families and dwellings.
Each topic is represented on the Census form by one or more questions, each of which collects information about a particular data item, commonly called a variable. For example, information about persons includes the topic 'labour force'. The variables associated with the topic 'labour force' include hours worked, labour force status and occupation.
A variable may take a range of values. For example, the variable sex can take the values 'male' or 'female'. The range of values available for a variable is referred to as its classification. Each value of a variable is referred to as a category, or class, of the classification. Thus sex has two categories, 'male' and 'female'. Often the name used for a variable is also used for its classification, as in the case of the variable sex.
For efficient computer processing, and for specifying the order in which the categories of a classification are presented in a table or report, the categories of a classification are recorded in computer records as numbers. For the variable sex, the category 'male' is represented by the code number '1', and the category 'female' is represented by the code number '2'. Typically a classification is defined by a list of category descriptions and their corresponding codes.
Computer processing of Census forms immediately following a Census is largely concerned with the allocation of appropriate codes from the responses to the questions on the forms. When tables are generated from the coded Census file, the classifications making up the table are usually presented in terms of their category descriptions as well as, or in place of, their code.
The Census uses Australian standard classifications where available and appropriate. Examples of these are the Australian and New Zealand Standard Classification of Occupations (ANZSCO) or the Standard Australian Classification of Countries (SACC). These Australian standard classifications are used as the basis for Census output classifications such as Country of Birth of Person which uses SACC. Australian standard classifications are reviewed on an irregular basis to reflect changes in Australian society. A summary of any changes to these classifications is provided in the section, New and Revised Classifications.
Where an Australian standard classification is not available, classifications specific to Census variables have been developed. Examples of such Census classifications are Child Type and Journey To Work. The categories of these classifications are reviewed prior to each Census. A summary of changes to Census variables is provided in the section, What's New for 2006 - Summary of Changes to Variables 2001 to 2006.
Each classification, or variable, listed in this dictionary has a mnemonic associated with it - for example, HIND for Household Income. Mnemonics are a convenient shorthand method of describing Census classifications when specifying output requirements. Each classification relates to either a dwelling (or household), family or person. The last character of the mnemonic indicates the unit to which the classification relates:
D indicates a classification that records a characteristic of a dwelling;
F indicates a classification that records a characteristic of a family; and
P indicates a classification that describes a characteristic of a person.
The classifications listed in this dictionary do not include the geographic classifications used to describe the geographic areas covered by the Census. Geographic classifications formed by the aggregation of Collection Districts (CDs), such as Statistical Local Areas (SLAs), Local Government Areas (LGAs) and Electoral Divisions are described in the publication Statistical Geography Volume 2: Census Geographical Areas, Australia (cat. no. 2905.0).
Additional geographic information can be found in Statistical Geography Volume 1: Australian Standard Geographical Classification (ASGC) 2006 (cat. no. 1216.0).