HOUSEHOLD, INCOME UNIT AND PERSON DATA
The SIH collects information with respect to households and all the people comprising those households. It is therefore possible to produce aggregate data from the survey to households, to persons, or with respect to combinations of persons within the household such as income units. Analysts can choose the unit of analysis most suited to their purposes. The data item list referred to in section 2.3 'Data collection and data item description' shows which data items are available for each unit type supported by the SIH.
A household consists of one or more persons, at least one of whom is at least 15 years of age, usually resident in the same private dwelling. The persons in a household may or may not be related. They must live wholly within one dwelling. A group of people who make common provision for food and other essentials of living but live in two separate dwellings are in two separate households.
Most of the published output from the SIH uses the household as the unit of analysis and relates to characteristics of the households.
An income unit is one person or a group of related persons within a household, whose command over income is assumed to be shared. Income sharing is assumed to take place within married (registered or de facto) couples, and between parents and dependent children. The income unit is similar, but not identical, to the unit used in determining the eligibility of people for many government pensions and allowances such as Centrelink payments.
Income data and selected income unit characteristics are available on an income unit basis from the SIH, although they are not included in any published output from the survey.
Data at the person level are available for each person aged 15 years and over usually resident in the households included in the SIH. Data relating to children under the age of 15 are only available at the household level.
Units used in SIH published output
Analysis of income data is usually carried out using household income measures. As explained in section 1.3 'Equivalised household income', is normally most appropriate to examine household income when considering economic wellbeing, because of the sharing that occurs between members of households. That section also explains that income comparisons are improved if the household income measure is adjusted to reflect the size and composition of the household.
However, when analysing income distribution, it is the number of people who belong to households with particular characteristics, rather than the number of households with those characteristics, that is of primary interest. This leads to the preference for the equal representation of those persons in such analysis. For example, if the person is used as the unit of analysis rather than the household, then the representation in the income distribution of each person in a household comprising four persons is the same as that for each person in a household comprising two persons. In contrast, if the household were to be used as the unit of analysis, each person in the four person household would only have half the representation of each person in the two person household. Therefore, the income distribution measures from the SIH are all calculated with respect to persons, including children. Such measures are sometimes known as person weighted estimates because the unit of analysis is the person, even though all the characteristics being described are characteristics of the household to which the person belongs. The method of calculation is described in section 2.7 'Calculation of population counts, means, medians and other estimates'.