The concept of household is fundamental in the production of social and labour statistics. The household is one of the basic units of social analysis and is the basis for data collection in many statistical collections. In the ABS, many social, labour and demographic surveys are household-based, including the Census of Population and Housing and the Labour Force Survey. The ABS 'Household composition' variable classifies households by the number of families or other people usually resident within them.

In its broadest sense a household is a group of people who live together as a single unit within a dwelling. Together with the family, it is one of the basic groups of social aggregation. Households and families are closely connected to each other and, although each concept is defined in different terms, in practice they often refer to the same set of people when applied to a particular dwelling. Information on households provides input to Australian household-based estimates. It also identifies various groups within the population, such as multiple family households or the number of people living alone. 'Household composition' can also be cross-classified with other variables, e.g. 'Total cash income'.

The name of the variable is 'Household composition'.

The primary factor determining 'Household composition' is whether a family is present or not and whether or not other unrelated household members are present. For statistical purposes, family is defined as two or more people, 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.

'Household composition' replaced the ABS Standard Variable 'Household type' in 2005. The title 'Household type' has been used to describe this variable in the Census of Population and Housing since 1986, the 1992 Survey of Families in Australia and the Monthly Population Survey (MPS). The title 'Family Composition of Household' has been used in the Household Expenditure Survey (HES). Prior to the introduction of the 'Household type' standard in 1992, the MPS used a non-standard list of family and household types labelled as 'Household Type'.

The concept of 'Household' is nominally defined as: 

• One or more persons usually resident in the same private dwelling.

The System of National Accounts (SNA) definition is: 'a small group of persons who share the same living accommodation, who pool some, or all, of their income and wealth and who consume certain types of goods and services collectively, mainly housing and food.' The ABS definition varies from that of the SNA only in specifically allowing lone person households, and in removing any reference to consumption.

The variable 'Household composition' is defined as:

• The differentiation of households on the basis of the number of families present, and whether or not unrelated household members are present (if it is a family household), or the number of household members (if it is a non-family household).

The variable 'Household composition' is an attribute of the statistical unit 'household'. Indirectly it is also an attribute of the 'person' for all persons who are members of households.

The 'Household' is operationally defined as:

• One or more persons, at least one of whom is at least 15 years of age, usually resident in the same private dwelling.

The ABS does not seek to differentiate multi-household dwellings from single-household dwellings; the number of households in a private dwelling is always regarded as one.

Having established the relationship of all usual residents of the household to one another, and identified all families and other unrelated household members (if any) within the household, the operationalisation of 'Household composition' is summarised as follows:

• Households are allocated to categories of the 'Household composition' classification on the basis of the number of families identified in the household, whether unrelated household members are present in a family household and whether the number of household members is greater than one in a non-family household.

The identification of usual residents is essential to determine 'Household composition' because the 'Relationship in household' data on which family and household coding rely only applies to usual residents.

For those cases where visitors are within scope of the collection, households consisting of visitors only are coded to Supplementary category '02 Visitor only household'.

Household member relationships and family identification are carried out using the 'Relationship in household' and 'Family composition' classifications. For further details see the standards for those variables

The variable 'Household composition' applies to all households in private dwellings

The variable 'Household composition' aims to analyse the counting unit 'household', just as the variable 'Family composition' is used in analysing the counting unit 'family' and the variable 'Income unit composition' is used to group persons within households who pool income in social and labour statistical collections. The income unit, the family and the household describe concepts which are very closely related in practice. Even though they are fundamentally different ideas, when applied to a particular dwelling they will all often refer to the same set of people. This is because the family is defined as a subset of the household and many Australian households comprise only a single family and a single income unit.

The 'Household composition' classification does not distinguish between multifamily households where the families are related to each other (e.g. where siblings each with dependent children share a dwelling), and multifamily households where the families are not related to each other. If this distinction is required, it should be derived as the separate variable 'Relationship between families' using 'Relationship in household' data. See the 'Relationship between families' standard for more information. The 'Household composition' classification does not distinguish between income units.

The 'Household composition' concept is confined to private dwellings. In some surveys, a multi-stage area sample of dwellings separately identifies two categories of dwellings: private dwellings (houses, flats, etc.) and non-private dwellings (or 'Special dwellings') which include units such as hotels and motels. Persons living in non-private dwellings such as hospitals, prisons, homes for the aged, etc. are outside the scope of the classification.

Hotels, motels and serviced apartments may be thought to contain potential households, but the ABS excludes people in non-private dwellings from family coding due to operational constraints imposed by the nature of collection methodologies. Similarly in the case of the Census, household data are not collected from persons residing in non-private dwellings, either temporarily or for longer periods of time. Instead, each individual is administered a personal questionnaire. Consequently the Census does not identify households in non-private dwellings either. It should be noted that over time the types of dwellings categorised as private dwellings have expanded to include some retirement villages, caravans etc, effectively broadening the scope of dwellings considered private dwellings.

The criteria used to structure the 'Household composition' classification are: 

• The presence or absence of families in a household.
• The number of families in a family household.
• The presence of non-family members.
• Whether there is more than one household member in a non-family household.

The standard 'Household composition' classification comprises the following categories:

The 'Household composition' classification contains three supplementary codes:

• '1 Not stated/inadequately described'.
• '2 Visitor only household'.
• '3 Other not classifiable'.

The first code is used to code responses which do not provide sufficient information to be coded to any level of the structure or when no information is given. The second is used when all of the individuals present are visitors and such households fall within the scope of a particular collection. The third category is used to process responses which are not within the scope of the classification, for example when all of the individuals present are under 15 years old.

The 'Household composition' classification is designed to classify all households within all private dwellings in Australia. Household data are not sought from persons usually resident in non-private dwellings, which are out of scope of the classification (see the 'Discussion of conceptual issues' section on the 'Underlying Concepts' page for further information).

Operationally, any dwelling where all members are aged under 15 years is out of scope of the classification and therefore coded to '03 Other not classifiable'. This approach is consistent with that used in the 'Family composition' classification.

Although 'Household composition' is an attribute of the counting unit Household, where output requires, families and persons may be classified by the 'Household composition' of their household.

The 'Household composition' classification should only be applied to the variable 'Household composition'.

The standard classification and codes for 'Household composition' are derived from 'Relationship in household' and 'Family composition' data. Responses to the 'Household composition' variable are stored as codes of the classification.

The data used to form the input to the 'Household composition' classification are derived from those collected to derive the 'Relationship in household' and 'Family composition' variables. The recommended methodology and questionnaire modules are explained in the 'Relationship in household' standard.

The derivation of the input categories can be summarised as follows:

The relationship of all household members to one another is established. Then all families and other unrelated household members (if any) within the household are identified. 'Household composition' is then allocated on the basis of the number of families and whether unrelated household members are present (if it is a family household) or the number of household members if it is a non-family household.

The original answers to the questionnaire module must therefore be processed to produce the following input to the 'Household composition' classification: 

• the presence or absence of families in a household
• the number of families present in a family household, and
• whether unrelated persons are present in a family household, or
• whether there is more than one person present in a non-family household.

This information can be taken directly from that already processed to obtain 'Relationship In household' and 'Family composition'.

To represent the full range of household structures in statistical output, it is anticipated that most users and producers of household statistics will present data using the full classification structure. If output is to be presented in a nested or hierarchical manner, then the standard output labels are:

If output is to be presented at one level only there are several options of standard output labels depending on the output purposes and requirements.

Many users are interested in an output structure that focuses on particular aspects of the data collected. In such cases, combining the output of the 'Family composition' variable with that of the 'Household composition' variable will be most useful. For example, they may be interested in the presence of absence of dependent children within the family (from 'Family composition') and whether people other than just these parents and their dependent children are also present in the household (from 'Household composition'). Such other people are non-dependent children, other related individuals in the family, or non-family members in the household.

Published output uses either detailed or short output structures and both should be labelled 'Family composition of household'. The same title is applied to both structures because the short structure is an aggregation of some categories of the detailed structure and is thus fully compatible.

The first (and more detailed) recommended standard cross-classified output structure follows. This output structure has mandatory explanatory requirements in the form of footnotes or glossary entries which are detailed in the 'Summary information' section below.

If required, the output can feature two extra subtotals:

• Total households with dependent children.
• Total households with no dependent children.

The categories of the detailed output structure provided above may be aggregated in a variety of ways in order to best fulfil user requirements. For example separate information on Lone persons and Group households may not be required, in which case output could be published at the Non-family household level. However, in the interests of comparability across collections a shorter aggregated version of the structure is explained below and is recommended for use where possible.

The detailed information required to construct this output tabulation is too lengthy for inclusion as footnotes to the table. This information is specified below under the heading 'Detailed description of table categories'. The summary information below outlines the information contained in the detailed description to aid interpretation of the table: it should be included as footnotes, in a glossary or as explanatory material to any published output.

Summary information aids interpretation of the output table and should be included as footnotes, in a glossary or as explanatory material to any published output. The information required is:

1. The expression 'Other persons' refers to non-dependent children, other related individuals, and non-family members in the household.
2. The categories 'Couple family with dependent children only', 'One parent family with dependent children only' and 'Couple only' do not contain any non-dependent children, any related individuals, or any non-family members in the household.
3. The category 'Other one family households' comprises the 'Family composition' categories 'Other family' and 'One parent family with no children under 15, no dependent students and with non-dependent children'.

The following information defines the exact content of each category in the detailed output structure above:

a. Dependent children are children aged under 15 years, and dependent students (i.e. full-time students aged 15-24 years).

b. The expression 'Other persons' refers to non-dependent children, other related individuals, and non-family members in the household.

c. 'Other related individuals' are persons who report one of the following 'Relationship in household' to the Family reference person:

61 Brother/sister
62 Father/mother
63 Non-dependent grandchild
64 Grandfather/grandmother
65 Cousin
66 Uncle/aunt
67 Nephew/niece
69 Other related individual not elsewhere classified

They are identified by cross-classification of the family with 'Relationship in household' data.

d. The categories 'Couple family with dependent children only', 'One parent family with dependent children only' and 'Couple only' do not contain any non-dependent children, any related individuals, or any non-family members in the household.

e. The category 'Couple family with dependent children only' comprises the following 'Family composition' categories, where the 'Household composition' category is '11 One family household with only family members present', and no 'other related individuals' are present:

• 2112 Couple family with children under 15, dependent students and no non-dependent children
• 2122 Couple family with children under 15, no dependent students and no non-dependent children
• 2212 Couple family with no children under 15, and with dependent students and no non-dependent children

f. The category 'Couple family with dependent children and other persons' includes the following 'Family composition' categories:

• 2111 Couple family with children under 15, dependent students and non-dependent children
• 2121 Couple family with children under 15, no dependent students and with non-dependent children
• 2211 Couple family with no children under 15, and with dependent students and non-dependent children

It also includes the following 'Family composition' categories where the 'Household composition' category is '12 One family household with non-family members present', or when 'other related individuals' are present:

• 2112 Couple family with children under 15, dependent students and no non-dependent children
• 2122 Couple family with children under 15, no dependent students and no non-dependent children
• 2212 Couple family with no children under 15, with dependent students and no non-dependent children

g. The category 'One parent family with dependent children only' comprises the following 'Family composition' categories, where the 'Household composition' category is '11 One family household with only family members present', and no 'other related individuals' are present:

• 3112 One parent family with children under 15, dependent students and no non-dependent children
• 3122 One parent family with children under 15, no dependent students and no non-dependent children
• 3212 One parent family with no children under 15, with dependent students and no non-dependent children

h. The category 'One parent family with dependent children and other persons' includes the following 'Family composition' categories:

• 3111 One parent family with children under 15, dependent students and non-dependent children
• 3121 One parent family with children under 15, no dependent students and with non-dependent children
• 3211 One parent family with no children under 15, and with dependent students and non-dependent children

It also includes the following 'Family composition' categories where the 'Household composition' category is '12 One family household with non-family members present', or when 'other related individuals' are present:

• 3112 One parent family with children under 15, dependent students and no non-dependent children
• 3122 One parent family with children under 15, no dependent students and no non-dependent children
• 3212 One parent family with no children under 15, with dependent students and no non-dependent children

i. The category 'Couple only' comprises the 'Family composition' category '1222 Couple family with no children', where the 'Household composition' category is '11 One family household with only family members present', and no 'other related individuals' are present.

j. The category 'Other one family households' comprises the 'Family composition' category '1222 Couple family with no children', where the 'Household composition' category is '12 One family household with non-family members present'; and the 'Family composition' categories '2221 Couple family with no children under 15, no dependent students and with non-dependent children'; '3221 One parent family with no children under 15, no dependent students and with non-dependent children'; and '9222 Other family'.

The second (and more concise) standard output structure is shown below. It represents an aggregated version of the detailed structure above and is fully compatible with it. Any table produced using this structure has mandatory explanatory requirements in the form of footnotes or glossary entries which must be listed beneath the resulting table.

The variable 'Household composition' is primarily used as a stand-alone variable but can be used in conjunction with many other variables to increase the explanatory power of the classification. 'Relationship in household' and 'Family composition' are required in order to determine 'Household composition'.

Over time the types of dwellings considered as private dwellings have expanded to include caravan parks and some retirement villages. Therefore while the actual scope of the 'Household composition' variable remains the same, the population of persons considered to be within that scope has expanded to enable such households to be enumerated. No other specific measurement issues apply to the variable 'Household composition' beyond the normal constraints affecting statistical collections, such as problems with confidentiality or standard errors which may not permit the output of data for some of the categories at the more detailed levels of the classification.

The 'Household composition' classification is closely linked to the following classifications:

• 'Family composition'.
• 'Relationship In household'.
• 'Income unit composition'.
• 'Social marital status'.

Changes to any of these classifications cannot be considered in isolation and all possible ramifications concerning the other classifications must be investigated before adopting the change.