"Income bands are a convenient and alternate way of collecting income information when income is not the prime focus of a survey. Bands reduce respondent burden by providing a simple way to obtain contextual information about income. Income bands are often tabulated with other variables such as age, occupation and education qualifications to provide information on the relationship between these variables and the income distribution of the population.
In addition, when income information has been collected as dollar amounts, it may be output as income bands. This provides statistics on the distribution of income across the population, which is not provided by average income.
Income band statistics are used extensively within Statistics New Zealand, across government, and by other agencies and academics for: formulating social and economic policy; calculating school deciles; use as an indicator for poverty statistics and the New Zealand Index of Deprivation; research and planning; monitoring programmes."