Latest release

Relationship between families (FRLF)

Census of Population and Housing: Census dictionary
Reference period


This variable describes the relationship between families within a household. The variable Family number (FNOF) is required to identify the primary, second or third family counted within the household.

The relationship described is between the primary family and the second or third family. For example, in a household there is a primary couple family with children and a second couple family. The second family consists of the parents of the reference person in the primary family. This second family would be identified as ‘Mother’s/father’s family.


Two or three family households




Mother's/father's family


Grandparent's family


Son's/daughter's family


Grandchild's family


Brother's/sister's family


Other related family


Unrelated family


Not applicable

Number of categories: 8

Not applicable (@) category comprises:

  • Primary families in multi-family households
  • One family households
  • Non-family/Non-classifiable households
  • Unoccupied private dwellings
  • Non-private dwellings
  • Migratory, off-shore and shipping SA1s

Question(s) from the Census form

What is the person’s relationship to Person 1/Person 2?

    What is Person 2's relationship to Person 1?
    What is Person 2's relationship to Person 1?

    Examples of other relationships: Son-in-law, Grand-daughter, Uncle, Boarder.

    More information

    Husband or wife of Person 1

    De facto partner of Person 1

    Child of Person 1

    Stepchild of Person 1

    Brother or sister of Person 1

    Unrelated flatmate or co-tenant of Person 1

    Other relationship to Person 1 (please specify)

      More information

      Additional information relating to the question on: What is Person 2's relationship to Person 1?

      More information

      What is Person 2's relationship to Person 1?

      Examples of other relationships: Son-in-law, Grand-daughter, Uncle, Boarder.

      More information

      If more than one response applies, select only the option that shows the relationship that most closely applies.

      How this variable is created

      This variable is derived from the Relationship in household question on the Census form. This question is used to determine the relationships people have with others in a multi-family household. Persons temporarily absent are also taken into consideration.

      History and changes

      This variable was first introduced in 1991.

      No changes have been made for 2021.

      Data use considerations

      Relationship between families categories of 'Mother's/father's family' (FRLF category 1) and 'Son's/daughter's family' (FRLF category 3) are complementary. To find the number of families living with a family that contains a parent or child of one of the family members, users should consider both categories combined.

      Users are faced with a similar situation when looking at 'Grandparent's families' and 'Grandchild families' (FRLF categories 2 and 4). Any one of these categories used in isolation will not give a full count of family pairs bound by a specified relationship.

      During data processing the relationships identified are used to derive the relationship of each family to the household’s ‘primary family’. A 'primary family' is an ABS term that is used to aid coding of household relationships, and should not be misinterpreted as signifying the family that owns the house, or the 'main' family for any reason other than ABS family and household coding purposes.

      Related variables and glossary terms

      Other ABS sources