1286.0 - Family, Household and Income Unit Variables, 2005  
ARCHIVED ISSUE Released at 11:30 AM (CANBERRA TIME) 01/06/2005   
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Contents >> Family composition >> Underlying concepts

This document was added or updated on 23/04/2007.



5. The name of the variable is 'Family composition'.


Nominal definition

6. The nominal definition of 'Family composition' is more restrictive than the ordinary notion of the term 'family' which generally includes relatives whether they live together or not. This is because in survey research it is necessary to place some physical bound on the extent of family for the purely pragmatic purpose of being able to collect family data. Consequently the ABS has adopted a more restricted definition of 'family' as the basis for determining 'Family composition'.

7. The concept of 'family' is defined as:

  • Two or more related people who usually live together.

8. This definition illustrates three fundamental bounds on the concept of Family at a broad level. These restrictions are:
  • a family must consist of more than one person,
  • family members must be related,
  • family members must live in the same household.

9. Families can be differentiated using many identifiable characteristics such as the number of children in the family or the size of the family. This standard makes it possible for families to be identified and further differentiated into different types of families based upon certain relationships between members of the family.

10. The variable 'Family composition' is nominally defined as:
  • The composition of the family based on the relationships between family members usually resident in the same household.

11. 'Family composition' is an attribute of the counting unit 'family', and by extension of the counting unit 'person' for all persons who are members of families.

Operational definition

12. Operationally, 'family' is defined as:
  • Two or more persons, one of whom is at least 15 years of age, who are related by blood, marriage (registered or de facto), adoption, step or fostering, and who are usually resident in the same household. The basis of a family is formed by identifying the presence of a couple relationship, lone parent-child relationship or other blood relationship. Some households will, therefore, contain more than one family.

13. A detailed and lengthy set of rules is required in order to specify a fully defined and rigorous operational methodology for identifying individual families. The rules are specified in this standard in the section on Coding procedures.

14. The operational definition clarifies the bounds on 'family' established in the nominal definition; most importantly, that a family is constrained within a household and only consists of related people 'usually resident' within that household (related people includes all child dependency relationships even though a child under the age of 15 may be unrelated to the family reference person). The definition of 'household' is therefore fundamental to the definition of 'family'. Following is a summary of the important points arising from this definition:
  • a family must consist of at least two persons, one of whom is at least 15 years of age.
  • as family is identified only from persons who are usually resident within a specific household, family members living in another household are excluded from being part of the same family.
  • registered and de facto marriages are accorded equal status.
  • non-related individuals living in the same household (eg. friend, boarder, housekeeper) are not counted as family members if they are 15 years of age or over.
  • separate families are identified within a single household if more than one group of people satisfy the criteria for forming a family. (All related individuals not forming a separate family within a household, however, are assigned as members of one and only one family). This is an important qualification of the nominal definition.

15. Operationally, 'Family composition' is defined as:
  • The differentiation of families based on the presence or absence of couple relationships, parent-child relationships, child dependency relationships or other familial relationships, in that order of precedence.

16. The specification of a rigorous methodology for operationalising 'Family composition' is outlined in the section on 'Rules for identifying families'. The following paragraph provides an encapsulation of the main features of the methodology.

17. The 'Family composition' of a particular family is operationalised by enumerating certain relationships that exist between a single 'family reference person' and each other member of that family. 'Family composition' is then allocated on the basis of whether the types of relationships given below are present or not in the family in the following order of precedence:
  • couple relationship - defined as a registered or de facto marriage;
  • parent-child relationship - defined as a relationship between two persons usually resident in the same household. The child is attached to the parent via a natural, adoptive, step, foster or child dependency relationship. For information on 'nominal children' see the section on Discussion of conceptual issues below.
  • child dependency relationship - defined as including all children under the age of 15 (whether related or unrelated to the family reference person) and those natural, step, adopted or foster children who are full-time students 15-24 years of age.
  • other relationship - defined as including all those persons related by blood or by marriage who are not covered by the above relationships.

18. As an example of the application of the above 'precedence rules' using the methodology described in the section on 'Rules for identifying families', consider the example of two elderly brothers living with the family of the daughter of one of the brothers. The daughter's family forms the basic family of the household and the two brothers are both allocated to this family unit as related individuals. The two brothers do not form a separate family in their own right in addition to the daughter's family, because they are related to a couple family or one-parent family already present in the household. However, if the two brothers were living in a dwelling with a family to whom they were not related, they would then form a family in their own right and be classified as an 'other family'.

Scope of the variable

19. The variable 'Family composition' applies to all families.


20. 'Family composition' requires the supporting variables 'Relationship in household' and 'Age'.


Nominal child and nominal parent

21. In many households in Australia the relationships between persons and the composition of those households are more diverse than those generally regarded as being traditional 'nuclear' families. Often the relationships between adults in the household and dependent children (persons aged under 15 or full-time students aged under 25) would not be captured by basic coding methods as explained in the 'Relationship in household' standard. In order to better reflect the nature of those relationships, where to all intents and purposes a 'parent-child' relationship exists, the ABS uses the concepts of the 'nominal child' and 'nominal parent'. The use of 'nominal child' and 'nominal parent' allows these relationships to be captured while maintaining a relatively simple set of family arrangements for analytical purposes.

22. For rules on when a 'nominal child' (and 'nominal parent') is created in family coding, see the section below on the 'Nominal child rules' in 'Coding procedures'.

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