Rates
Population rates enable different groups to be compared, while taking into account different population sizes. Because there are differences between the states and territories in the extent to which young people aged 18 or over can be detained in youth justice facilities, rates are restricted to those aged 10–13, 14–17 and 10–17. Crude rates are presented in this report.
The number of young people in detention on an average night during a quarter is rounded to the nearest person in text. The rate is calculated using the number on an average night before rounding.
In the text of this report, rates are presented to one decimal place for rates less than 10, and to the nearest whole number for rates 10 and over. Rates are presented to 3 decimal places in the supplementary tables. As a result, rates calculated by using the average nightly population rounded to whole numbers might differ slightly from the rates presented in this report.
Due to a lack of statistical reliability, rates are not calculated where there are fewer than 5 young people in the numerator. In some instances, the number of young people might be presented as 5, but the rate might not be calculated due to rounding (for example, if there are 4.7 young people in detention on an average night, this will appear as 5 in the table, but the rate will not be calculated). But these young people contribute to overall state and national rates. The calculation of rates for young First Nations and non-Indigenous Australians excludes young people with unknown Indigenous status.
In August 2023, the Northern Territory raised the minimum age of criminal responsibility from 10 to 12. The rates for the Northern Territory in 2023–24 are for young people aged 12–17 (instead of 10–17) and 12–13 (instead of 10–13).
In November 2023, the Australian Capital Territory raised the minimum age of criminal responsibility from 10 to 12. The rates for the Australian Capital Territory in 2023–24 are for young people aged 12–17 (instead of 10–17) and 12–13 (instead of 10–13).
Previously, there were slight differences between the total Australian population and the sum of states, as the Australia total included Other Territories. Due to the changes to the minimum age of criminal responsibility in the Northern Territory and the Australian Capital Territory, the population for Australia was manually calculated to exclude 10- and 11-year-olds in the Australian Capital Territory and Northern Territory for 2023–24. As a result, the Australia total excludes Other Territories and is calculated as a sum of states for the 10–13 (12–13 for the Australian Capital Territory and Northern Territory), 14–17 and 10–17 (12–17 for the Australian Capital Territory and Northern Territory) age groups.
Population data used in the calculation of rates are provided in the supplementary tables S55a, S55b and S55c.