Juvenile Justice National Minimum Data Set Data Quality Statement
Identifying and definitional attributes
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Summary of Key Issues
The youth justice system is the set of processes and practices for dealing with children and young people who have committed or allegedly committed offences. In Australia, youth justice is the responsibility of state and territory governments, and each state and territory has its own youth justice legislation, policies and practices.
The JJ NMDS contains information on all children and young people in Australia who are supervised by youth justice agencies, both in the community and in detention.
Each year, the state and territory government departments responsible for youth justice supply data to the AIHW under a memorandum of understanding between the Australasian Juvenile Justice Administrators (AJJA) and the AIHW. Those data are compiled into the JJ NMDS.
The AIHW is a major national agency set up by the Australian Government under the Australian Institute of Health and Welfare Act 1987 to provide reliable, regular and relevant information and statistics on Australia’s health and welfare. It is an independent statutory authority established in 1987, governed by a management board and accountable to the Australian Parliament through the Health and Ageing portfolio.
The AIHW aims to improve the health and wellbeing of Australians through better health and welfare information and statistics. It collects and reports information on a wide range of topics and issues, ranging from health and welfare expenditure, hospitals, disease and injury and mental health to ageing, homelessness, disability and child protection.
The Institute also plays a role in developing and maintaining national metadata standards. This work contributes to improving the quality and consistency of national health and welfare statistics. The Institute works closely with governments and non-government organisations to achieve greater adherence to those standards in administrative data collections to promote national consistency and comparability of data and reporting.
One of the main functions of the AIHW is to work with the states and territories to improve the quality of administrative data and, where possible, to compile national data sets based on data from each jurisdiction, to analyse the datasets and disseminate information and statistics.
The Australian Institute of Health and Welfare Act, in conjunction with the compliance provisions of the Privacy Act 1988 (Cwth), ensures that the data collections managed by the AIHW are kept securely and under the strictest conditions to preserve privacy and confidentiality.
For further information, see the AIHW website <www.aihw.gov.au/>.
The reference period for the 2012–13 JJ NMDS is from 1 July 2000 to 30 June 2013. This means that in 2012–13, data were resupplied for the period 2000–01 to 2011–12, and data for 2012–13 were supplied for the first time. The data set includes young people who were under youth justice supervision at any time during that period.
The state and territory departments responsible for youth justice provide data to the AIHW annually, following the end of each financial year. For the 2012–13 collection, the first iteration of data was due to the AIHW within 3 months of the end of the financial year (by 30 September 2013). Two of six jurisdictions supplied data within 3 months of the end of the financial year, and all participating jurisdictions supplied within 4 months. Data were finalised on schedule for all participating justisdictions by January 2014.
The first release of JJ NMDS data for each collection period occurs in the Youth justice in Australia bulletin (previously Juvenile justice in Australia). Subsequent publication of these data may occur in other AIHW bulletins and reports, and other publications external to the AIHW.
For the second time, data from the 2012–13 JJ NMDS are expected to be published in April of the year following the reference period (10 months after the end of the reference period). In previous years, data were expected to be published in August (14 months after the end of the reference period).
Publications containing JJ NMDS data, including the annual Youth justice in Australia bulletin and online appendix tables, are available on the AIHW website <www.aihw.gov.au/juvenile-justice-publications/>. These reports and tables are available free of charge.
Additional information about youth justice in Australia is available from <http://www.aihw.gov.au/juvenile-justice/>.
Requests for unpublished JJ NMDS data can be made by contacting the AIHW on (02) 6244 1000 or via email to [email protected]. A cost recovery charge may apply to requests that that take longer than half-an-hour to compile. Depending on the nature of the request, requests for access to unpublished data may require approval from the AJJA and/or the AIHW Ethics Committee.
General inquiries about AIHW publications can be made to the Communications, Media and Marketing Unit on (02) 6244 1032 or via email to [email protected]
Detailed supporting information on the quality and use of JJ NMDS data is available from the AIHW website at <www.aihw.gov.au/juvenile-justice/>. AIHW youth justice reports are available for purchase in hard copy or for download free of charge from <www.aihw.gov.au/juvenile-justice-publications/>. Readers are advised to consider supporting information to ensure appropriate interpretation of analyses presented by the AIHW. Supporting information includes footnotes to tables and details of the data items, coverage, quality and the methods used in reporting, such as the calculation of counts, rates and supervision periods.
Metadata for the JJ NMDS is available in METeOR, the AIHW’s online metadata repository. METeOR specifications for the collection can be accessed at </content/index.phtml/itemId/470084>.
The JJ NMDS contains information on all children and young people who were supervised by a youth justice agency in Australia during the reference period because they:
In Queensland, youth justice legislation applies to children and young people aged 10–16 when the offence was committed or allegedly committed. In all other states and territories, youth justice legislation applies to young people aged 10–17. Although most young people under youth justice supervision are aged 10–17, some are aged 18 and over.
For each young person recorded in the JJ NMDS, data are collected on sex, date of birth, Indigenous status and date of first supervision.
The JJ NMDS contains information on all supervised legal arrangements and orders that youth justice agencies administer (both community-based and detention orders) and all periods of detention in youth justice detention centres.
Supervised legal arrangements and orders include police-referred detention before the first court appearance; court-referred remand; supervised bail; and sentenced orders, such as community service orders, probation, suspended detention, sentenced detention and parole or supervised release.
Periods of detention include police-referred detention (before the young person’s initial court appearance), remand (court-referred detention following a court appearance) and sentenced detention.
For each period of supervision, data are collected on:
The JJ NMDS does not contain information on children and young people in the youth justice system who were not supervised (for example, young people on unsupervised bail), or who were supervised by other agencies, such as police.
Data published in the Youth justice in Australia bulletins include numbers and rates of young people under supervision both on an average day and during the year, the characteristics of those young people and information on the types of supervision they experienced.
Data for the JJ NMDS are extracted each year from the administrative systems of the state and territory departments responsible for youth justice in Australia, according to definitions and technical specifications agreed to by the departments and the AIHW.
Overall, the coverage of data in the JJ NMDS are very good. About 7% of all young people in the JJ NMDS since 2000–01 have an unknown Indigenous status, and similar proportions of records in each of the order (7%) and detention (6%) files have unknown or missing information for the postcode and suburb of the young person’s usual residence. For all other variables in the JJ NMDS, the proportion of missing data is 1% or less.
Each year, most jurisdictions supply data from 2000–01 to the most recent financial year, incorporating updates to data as required. Trend data may therefore differ from those published in previous Youth justice in Australia reports due to data revisions. The most recent data are the most accurate.
There are a number of data quality and coverage limitations specific to each state and territory. In particular, Western Australia and the Northern Territory did not provide JJ NMDS data for the years 2008–09 to 2012–13, and some states and territories did not provide data in the current format for all years of the JJ NMDS (2000–01 to 2012–13). As a result, two types of national totals are calculated for publications where possible—totals based on JJ NMDS data only (excluding Western Australia and the Northern Territory), and estimated national totals that include all states and territories.
In addition, some analyses of trends exclude those states and territories with incomplete data in the new format due to comparability issues. Readers are advised to read the supporting information in publications (such as footnotes to tables and details of the methods used to compile the data) to ensure appropriate interpretation.
Data quality issues specific to each state and territory include the following:
New South Wales
In New South Wales, the Kariong Juvenile Justice Centre was transferred from the NSW Department of Juvenile Justice to the NSW Department of Corrective Services on 10 November 2004 and renamed the Kariong Juvenile Correctional Centre. As the JJ NMDS includes only young people who are supervised by youth justice agencies in Australia, information about young people in custody in the Kariong Juvenile Correctional Centre after 10 November 2004 is not included. There are typically 18–28 young people on an average day in the Kariong Juvenile Correctional Centre, and therefore they form only a small proportion (around 5%) of young people in detention in New South Wales.
Western Australia did not provide JJ NMDS data for 2008–09 to 2012–13. For these years, only limited data in a non-standard format were provided. These data include the number under community-based supervision and in detention at the end of each month, and additional data on community-based orders and detention placements. These data contribute to the national totals where possible, but are not reliable enough for separate reporting.
Data for Western Australia for 2000–01 to 2007–08 are available only in the JJ NMDS 2007 format. Some trend analyses therefore exclude Western Australia. These data were extracted from separate detention and community-based supervision databases and linked using a statistical linkage key. While this linkage is sufficiently accurate for statistical purposes, it is not accurate for administrative purposes such as case management.
Data from South Australia for 2012–13 may vary from that reported in previous years due to improvements in data quality and assurance.
For Tasmania, complete data on detention periods and orders are available only for 2006–07 onwards. Because data on length of detention is used to derive the time spent under community-based supervision, information on periods of community-based supervision before 2006–07 may therefore be incomplete and are not reported.
Australian Capital Territory
For the Australian Capital Territory, data for 2000–01 to 2002–03 are not available and data for 2003–04 to 2007–08 are available only in JJ NMDS 2007 format. Some trend analyses therefore exclude the Australian Capital Territory.
In the Australian Capital Territory, both police-referred pre-court detention and remand (court-referred detention) are recorded as remand.
The end reasons for orders are not available for the Australian Capital Territory.
The Northern Territory did not provide JJ NMDS data for 2008–09 to 2012–13. Data for 2000–01 to 2007–08 are available only in JJ NMDS 2007 format. Some trend analyses therefore exclude the Northern Territory.
Data for 2007–08, which are the most recently available JJ NMDS data for the Northern Territory, are used in the national totals where possible, but are not reliable enough for separate reporting.
The JJ NMDS was initially developed between 2002 and 2004, and the first report containing data from the JJ NMDS was published in 2006. This first version of the JJ NMDS (referred to as JJ NMDS 2007 on METeOR) contained information on only the most serious supervised legal arrangement or order for each young person under youth justice supervision (see Juvenile justice in Australia 2007–08 for more information).
In 2009, the JJ NMDS was redeveloped to capture all supervised legal arrangements and orders for young people under youth justice supervision, rather than only the most serious one. This version of the JJ NMDS (known as JJ NMDS 2009) allows for more complete analyses of the numbers and types of supervised orders that youth justice agencies administer. Juvenile justice in Australia 2008–09 was the first report to contain data from the redeveloped JJ NMDS.
For the 2012–13 JJ NMDS collection, the reference period was 2000–01 to 2012–13. Data were resupplied for the period 2000–01 to 2011–12. Trend data may therefore differ from those previously published due to data revisions.
The JJ NMDS is also used to compile the AIHW’s Youth detention population in Australia report (previously Juvenile detention population in Australia), which is supplemented with additional data on the number of young people in detention at midnight at the end of each month in the most recently completed financial year. The report, Juvenile detention population in Australia 2013, contains JJ NMDS data up to and including 30 June 2012, supplemented with additional data for the period from July 2012 to June 2013.
These data differ from those published in the annual Youth justice in Australia reports in several ways. First, Youth detention population in Australia presents the average nightly population for each quarter, while Youth justice in Australia presents the average daily population and total population for each year. Second, young people who are concurrently unsentenced and sentenced are classified as sentenced in Youth detention population in Australia, but are counted as both sentenced and unsentenced (or once in the total population) in Youth justice in Australia. These differences ensure comparability between the JJ NMDS data and the end-of-month data, which are counts of the numbers of young people at midnight and do not distinguish those who are serving a sentence from those who are concurrently sentenced and unsentenced. For the years before July 2008, JJ NMDS 2009 data were used for all states and territories other than Western Australia, the Northern Territory and the Australian Capital Territory, for which JJ NMDS 2007 data were used. In addition, only end-of-month data were used for Western Australia and the Northern Territory for July 2008 onwards.
Data from the JJ NMDS are also reported in the annual Report on government services published by the Steering Committee for the Review of Government Service Provision, and were used in the Juveniles in detention in Australia reports published by the Australian Institute of Criminology (AIC). The two most recent AIC reports contain data from the JJ NMDS; these data are the number in detention on the last night of each quarter. Earlier reports published by the AIC contain end-of-quarter data supplied directly by the states and territories.
Source and reference attributes
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