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Census of Population and Housing: Census dictionary
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Same-sex couple

Two persons of the same sex who report a de facto or married partnership in the relationship question, and who are usually resident in the same household, are a same-sex couple.

See also Marital status, Relationship as reported for couples (RLCP) and Relationship in household (RLHP).

Second generation Australians

Second generation Australians are Australian-born people living in Australia, with at least one parent born overseas. 

See also Country of birth of person (BPLP), Country of birth of parents (BPPP), Understanding Migrant statistics in the Census and other data sources and Understanding and using Ancestry data.


Self-enumeration is the term used to describe the way Census data is collected. The Census forms are generally completed by householders (or individuals in non-private dwellings) rather than by interviewers, although interviewers are available in some areas.

Socio-Economic Index for Areas (SEIFA)

Socio-Economic Indexes for Areas (SEIFA) is an ABS product that ranks areas in Australia according to relative socio-economic advantage and disadvantage. The indexes are based on information from the Census.

SEIFA consists of four indexes: the Index of Relative Socio-economic Disadvantage (IRSD); the Index of Relative Socio-economic Advantage and Disadvantage (IRSAD); the Index of Education and Occupation (IEO); the Index of Economic Resources (IER).

Each index is a summary of a different subset of Census variables and focuses on a different aspect of socio-economic advantage and disadvantage.

Special purpose codes

Special purpose codes allow address data to be coded to a non-spatial value. This occurs where there is insufficient information to code to a physical geographic area. For example, responses with no fixed address or instances of incomplete location information.

Special purpose codes have been created for each hierarchical level within the Australian Statistical Geography Standard (ASGS) Main Structure. These codes are not spatial. They do not have a region associated with them in the various ASGS digital boundary sets.

In the Main Structure, special purpose codes relate to States/Territories, SA4s, SA3s, SA2s and SA1s. They are also included in other ASGS areas such as Greater Capital City Statistical Area (GCCSA) and in Non-ABS structures.

For more information, refer to the Australian Statistical Geography Standard (ASGS).

Special short form

The Special short form is used in most areas of Australia to enumerate people who are sleeping rough. It is in paper format only and field staff use it to interview this population group. It records details for one person only and contains a small subset (10) of the same questions as the Census household form.

To view a PDF version of the Special Short form, see Sample copies of the 2021 Census paper forms.

See also, Homelessness enumerationHousehold form and Improvised home.

Step child

In a couple family, a step child is a child who is either the natural child of one partner but not of the other, or who was reported as being the step child of both parents. As a consequence of relationship breakdown or the death of a spouse, some one parent families may also have children reported as step children.

In practice, a person is considered a step child if the response 'step' is given for that person, regardless of the individual's dependency status.

See also Child, Child type (CTPP) and Relationship in household (RLHP).

Supplementary codes

Most variables in the Census Dictionary have supplementary codes and categories. We use supplementary codes to code responses that do not fit into the main categories.

They include:

  • Not stated
  • Not applicable
  • Overseas visitor
  • Inadequately described
  • So described
  • Not further defined (nfd)
  • Not elsewhere classified (nec)

For further explanation of the supplementary codes, see Understanding supplementary codes in Census variables.

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