4363.0 - National Health Survey: Users' Guide, 2017-18  
ARCHIVED ISSUE Released at 11:30 AM (CANBERRA TIME) 30/04/2019   
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Household and family characteristics

Definition


A 'household' is defined as one or more persons, at least one of whom is aged 18 years and over, usually resident in the same private dwelling.

A '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 can contain more than one family.

Household level estimates are available from this survey for:

    • Dwelling tenure and characteristics
    • Phone (fixed or landline connection, mobile/smart phone)
    • Geographic location
    • Number of persons in household
    • Household composition
    • Family composition of household
    • Household income
    • Household smokers
    • SEIFA characteristics of the area in which the dwelling is located.

Selected items are discussed below, for all others please refer to relevant sections of this Users' Guide.

Population


Information was collected for all selected and non-selected persons in the 2017-18 NHS.

Methodology


Information was collected about the households and families to which people belong. This information enables some understanding of the situation in which people live, which may impact on their health and related characteristics.

In addition to the items describing the characteristics of household units, basic information is available about each member of the selected households. This enables the circumstances of the respondent to be better understood and provides scope to rework some items (e.g. equivalised income) to suit particular data needs. Items available for each member of the household are:
    • Age of person
    • Sex of person
    • Indigenous status
    • Registered marital status
    • Social marital status
    • Country of birth
    • Family composition
    • Relationship in household

Relationship in household and family composition are discussed further below. More information on the other topics are available in the Demographic characteristics chapter.

Number of persons in household

This refers to a count of persons who are usual residents of the household dwelling and members of the household to which the respondent belongs.

Additional output items are available including:
    • Number of adults in household
    • Number of persons in household over 14 years
    • Number of children aged 0-17 years in household
    • Number of children aged 0-14 years in household.

Household composition

This refers to the composition of the household, based on the information about the residents of the household provided by the responsible adult (ARA).

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

The 'Household composition' classification comprises the following categories:
    • One family household with only family members present
    • Two family household with only family members present
    • Three or more family household with only family members present
    • One family household with non-family members present
    • Two family household with non-family members present
    • Three or more family household with non-family members present
    • Lone person household
    • Group household.

Further information can be found in Family, Household and Income Unit Variables, 2014 (cat. no. 1286.0).

Family composition of household

This is a new item for NHS 2017-18 which combines the output of the 'Family composition' variable with that of the 'Household composition' variable. It attempts to create family structures within a household based on the relationships of the residents, prioritising any family with dependent children. This structure can include households where there are no familial relationships such as group households or lone person households.

The output categories are:
    • One family household
      • Couple family with dependent children
        • Couple family with dependent children only
        • Couple family with dependent children and other persons
        Blank row
      • One parent family with dependent children
        • One parent family with dependent children only
        • One parent family with dependent children and other persons
        Blank row
      • Couple only
        • Couple family
        Blank row
      • Other one family household
        • Other one family household
        Blank row
    • Multiple family household
      • Multiple family households with dependent children
        • Multiple family households with dependent children
        Blank row
      • Multiple family households with no dependent children
        • Multiple family households with no dependent children
        Blank row
    • Non-family household
      • Lone person
        • Lone person
        Blank row
      • Group household
        • Group household

'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. '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'.

For more information about the definition of a Dependent child see the Glossary.

Household income

As reported by the selected adult respondent - see Income sources.

Equivalised income


Differences in household types and compositions, and their requirements relative to income, can be taken into account by the application of equivalence scales. These scales are a set of ratios which, when applied to the income of different household or income unit types, produce standardised estimates of income which reflect the households' relative well-being. The modified OECD equivalence scale (1994) was used.

Equivalised income is derived by calculating an equivalence factor and then dividing income by that factor. The equivalence factor is built up by allocating points to each person in the household unit and summing those points. One point is allocated to the first adult in the unit, 0.5 points for each other person aged 15 years and over, and 0.3 points for each person aged less than 15 years. For example:
    • A single person household has a factor of one. Equivalised income is therefore the same as reported income.
    • A household comprising two adults and a child aged less than 15 years would have a factor of 1.8. Equivalised income for this household is therefore the household income divided by 1.8.

Equivalised income is available in dollar amounts and deciles.

Income deciles and quintiles


Income deciles are groupings that result from ranking either all households or all persons in the population in ascending order according to some characteristic, such as income, and then dividing the population into ten equal groups, each comprising 10% of the estimated population. The first decile contains the bottom 10%, the second decile contains the next 10%, and so on. Quintiles are derived by adding together the first and second decile for the first quintile, third and fourth decile for the second quintile, and so on.

To assist in the use and interpretation of income deciles or quintiles at the person or household level, it is necessary to exclude income which is not stated or not known. If one or more of the contributing person records in a household has a value of 'not known' or 'not stated', then household income and derived income deciles are set to '98. Not stated' or '99. Not known' as it is not possible to determine an accurate value. Records with these codes should be excluded when categorising higher income values, and when calculating means, medians and other summary statistics.

For the 2017-18 NHS, the dollar ranges covered by deciles in all income items can be found at Appendix 5: Income deciles.

Socio-economic Indexes for Areas (SEIFAs)


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

SEIFA 2016 is the latest version of this product and consists of four indexes:
    • The Index of Relative Socio-Economic Disadvantage (IRSD), which is derived from variables such as income, educational attainment, unemployment, and dwellings without motor vehicles. Attributes summarised by this index include low income, low educational attainment, high unemployment and jobs in relatively unskilled occupations
    • The Index of Relative Socio-Economic Advantage and Disadvantage (IRSAD), which is a continuum of advantage (high values), to disadvantage (low values), that takes into account variables like the proportion of families with high incomes, people with a tertiary education and employees in skilled occupations
    • The Index of Education and Occupation (IEO), which includes variables relating to the educational and occupational characteristics of communities, such as the proportion of people with a higher qualification or those employed in a skilled occupation
    • The Index of Economic Resources (IER), which focuses on variables concerning the income, expenditure and assets of families, such as family income, rent paid, mortgage repayments and dwelling size.

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

Data from the 2017-18 NHS has been output according to the SEIFA 2016 as well as the previous version SEIFA 2011. It is emphasised, however, that these indexes relate to the area in which the survey respondent lived, and are not necessarily indicative of an individual respondent's socio-economic status. The 2011 index scores have been mapped to the SA1 and SA2 levels on both a National and State basis. The Index of Relative Socio-economic Disadvantage is the SEIFA index most frequently used for analysis of health characteristics.

For further information about the 2016 indexes, see Census of Population and Housing: Socio-Economic Indexes for Areas (SEIFA), Australia, 2016 (cat. no. 2033.0.55.001).

SEIFA deciles/quintiles

SEIFAs are commonly used to group populations into deciles or quintiles of a particular index. In the NHS, this enables comparisons to be made between the health characteristics, for example, of people living in less advantaged areas with those in more advantaged areas.

SEIFA deciles/quintiles can be derived in two ways - area-based and population-based.

Area-based deciles

All areas are ordered from lowest to highest index score, then the lowest 10% of areas are given a decile number of 1, the next lowest 10% of areas are given a decile number of 2 and so on, up to the highest 10% of areas which are given a decile number of 10. This means that areas are divided up into ten equal sized groups, depending on their index score.

Population-based deciles

An alternative way of defining the deciles is to divide them into ten equal groups based on the number of people living in those areas. These deciles contain an equal number of people (or at least as can be best achieved) in each group, rather than an equal number of areas. These are called population-based deciles.

For the NHS, SEIFA decile items have been derived for Area-based groupings. Because all SA1, SA2, LGA, POA, SSC, SLA are not equal in size and because the NHS sample is not selected to ensure an equal sample distribution at these lower level geographies, this method does not result in an equal number of people (either records or weighted estimates) in each decile/quintile.

Confusion can arise about the ordering of the deciles/quintiles created from SEIFA indexes. ABS constructs all four indexes so that relatively disadvantaged areas (e.g. areas with many low income recipients) have low index values, and relatively advantaged areas (e.g. areas with many high income recipients) have high index values. Correspondingly, in ABS publications and other outputs, SEIFA deciles are numbered from decile 1 or lowest decile (most disadvantaged), to decile 10 or highest decile (least disadvantaged). Quintiles are labelled similarly.

For consistency, this ordering applies to all indexes, irrespective of whether they are named as indexes of advantage and/or disadvantage. Care needs to be taken in comparing SEIFA analyses undertaken by different agencies, as quintiles or deciles may be labelled in reverse order to the standard ABS order.

Family characteristics

The composition of specific families within households is available on the All Persons level. This can provide a more detailed understanding of the family unit to which a person belongs than provided at the Household level.

'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. The 'family composition' of a particular family is created through the relationships that exist between a single 'responsible adult' and each other member of that family living in the household. 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:
    • A couple relationship is defined as a registered or de facto marriage, including same-sex relationships.
    • A parent-child relationship is 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.
    • A child dependency relationship is 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 is defined as including all those persons related by blood or by marriage who are not covered by the above relationships.

Family composition is categorised as follows:
    • Couple family with no children under 15
      • Couple family with no children under 15 and no dependent students
      • Couple family with no children under 15 and no dependent students and no non-dependent children
        Blank row
    • Couple family with children under 15
      • Couple family with children under 15 and dependent students
      • Couple family with children under 15, dependent students and non-dependent children
      • Couple family with children under 15, dependent students and no non-dependent children
        Blank row
    • Couple family with children under 15 and no dependent students
      • Couple family with children under 15, no dependent students and with non-dependent children
      • Couple family with children under 15, no dependent students and no non-dependent children
        Blank row
    • Couple family with no children under 15
      • Couple family with no children under 15 and with dependent students
      • Couple family with no children under 15, and with dependent students and non-dependent children
      • Couple family with no children under 15, and with dependent students and no non-dependent children
        Blank row
    • Couple family with no children under 15 and no dependent students
      • Couple family with no children under 15, no dependent students and with non-dependent children
        Blank row
    • One parent family with children under 15
      • One parent family with children under 15 and dependent students
      • One parent family with children under 15, dependent students and non-dependent children
      • One parent family with children under 15, dependent students and no non-dependent children
        Blank row
    • One parent family with children under 15 and no dependent students
      • One parent family with children under 15, no dependent students and with non-dependent children
      • One parent family with children under 15, no dependent students and no non-dependent children
        Blank row
    • One parent family with no children under 15
      • One parent family with no children under 15 and with dependent students
      • One parent family with no children under 15, with dependent students and non-dependent children
      • One parent family with no children under 15, with dependent students and no non-dependent children
      • One parent family with no children under 15 and no dependent students
      • One parent family with no children under 15, no dependent students and with non-dependent children
        Blank row
    • Other family.

The definition of family used for the NHS is a more restrictive definition than the ordinary notion of the term 'family' which generally includes relatives whether they live together or not. This is a reflection of the fact that for survey-based research it is necessary to place some physical bound on the extent of family, for the purposes of being able to collect family data.

Relationship in household


Relationship in household was derived from information supplied by the responsible adult (ARA) who answered the initial survey questions for each household, about all usual residents of the household. It describes the relationship of each person in a household to the ARA (i.e. wife, son, not related). Output categories are:
    • Husband, wife or partner
    • Lone parent
    • Child under 15
    • Dependent student
    • Non-dependent child
    • Other related individual
    • Non-family member
    • Visitor.

For more information about the definition of a child under 15 and dependent student see Dependent child see the Glossary.

Data items

The questionnaire, data items and related output categories for this topic are available in pdf / Excel spreadsheet format from the Downloads page of this product.

Comparability with 2014-15


All items above are considered directly comparable between the 2017-18 and 2014-15 NHS except for Family composition of household which was added in NHS 2017-18.

More information regarding comparisons between 2014-15 NHS and previous cycles is available in the National Health Survey: Users' Guide, 2014-15 (cat. no. 4363.0).