In Australia, the state and territory governments are responsible for youth justice, which leads to some variations in legislation, policy and practice. In part, these variations explain differences among the states and territories in the numbers, rates and characteristics of young people under youth justice supervision.
Detailed information on the key elements of the youth justice systems, policies and programs in each state and territory (provided by the relevant youth justice agency), along with individual fact sheets outlining the most recent numbers in youth justice supervision are available here:
Nationally, the rate of young people aged 10–17 under supervision on an average day in 2015–16 was 21 per 10,000. This rate was lowest in Victoria, at 14 per 10,000, and highest in the Northern Territory, at 57 per 10,000. (The Northern Territory supplied non-standard data for the Juvenile Justice National Minimum Data Set during 2015–16. They are included in state and territory comparisons, where possible.)
Although young people in all states and territories were more likely to be under community-based supervision than detention, rates varied across jurisdictions.
There were also differences in the age profiles of young people under supervision among the states and territories, due to differences in legislation, policies and practices. In Queensland, young people aged 17 or over at the time that they allegedly commit offences are processed in the adult criminal justice system. This results in a younger population, on average, under youth justice supervision in Queensland. Conversely, in Victoria, some young people aged 18–20 may be sentenced to detention in a youth facility (known as the 'dual track' system) which results in an older population, on average. See also Age range for treatment as a young person.
The average length of time young people spent under supervision in 2015–16 was 182 days nationally, or 26 weeks. This varied between states and territories, ranging from 149 days (21 weeks) in South Australia to 219 days (31 weeks) in Tasmania.