CLASSIFICATION AND CODING
9. 'Total cash income' is a continuous variable whose values are grouped into categories representing equal proportions of the population being enumerated.
CLASSIFICATION CRITERIA
10. As Total cash income is a continuous variable there are no formal classification criteria. Where there is a requirement to aggregate data into groups the population is ranked by the value of the total cash income and divided into groups of equal size, known as 'quantiles'. The preferred output categories for Australian cash income statistics group the population into five equal groups, known as 'quintiles', or ten equal groups, known as 'deciles'.
11. Dollar values for decile/quintile cut-off points or for mean or median values may be included in published tables to provide additional information.
12. The classification of populations by income quantiles is useful as many analysts select the bottom income decile or quintile as an indication of the population at most risk of economic disadvantage or in poverty.