Census Income question
Care should be taken when interpreting income data because income data collected on the Census form may differ from that reported in a survey specifically designed to collect information on this topic. Further, some people did not answer the Census question on income, which affects the individual income data as well as the household income calculations. In the 2006 Census, 12% of the Indigenous population and 4% of the non-Indigenous population did not provide a response to the question on income.
Individual income data is provided for people aged 15 years and over. Household income is presented on an equivalised basis (i.e. adjusted using an equivalence scale to make comparisons between households of different compositions easier). It is calculated based on the individual incomes of residents of a household, excluding visitors. It is only relevant for households in which there were no temporarily absent adults and all incomes were fully stated.
Survey of Income and Housing
The calculation of household and personal income measures relies on information from the Survey of Income and Housing (SIH). SIH data in relation to the total population are used to estimate the median value for each of the income ranges against which individual income is reported in the Census. It is not known how appropriate these SIH total population medians are to those reported by the Indigenous population against these income ranges.
How to calculate equivalised disposable income
To calculate the equivalised disposable income of a household, each member of the household is allocated 'equivalence points'. Taking the first adult in the household as having a weight of 1 point, each additional person aged 15 years or older is allocated 0.5 of a point, and each child under the age of 15 years is allocated 0.3 of a point. Equivalised disposable household income is then derived by dividing disposable household income by a factor equal to the sum of the 'equivalence points' allocated to the household members. The equivalised disposable income of a single person household is the same as its unequivalised disposable income.
For information on income data collected in the Census, and the calculation of equivalised household income, see paragraphs 56-60 of the Explanatory Notes in Population Characteristics, Aboriginal and Torres Strait Islander Australians, (cat. no. 4713.0). Further information is available from Appendix 3 of Household Income and Income Distribution, Australia, 2005-06 (cat. no. 6523.0).