CHANGES TO OFFENCE DATA
The Australian Standard Offence Classification (ASOC) provides a basis for the standardised collection, analysis and dissemination of offence data within crime and justice statistics. For the 2010 reference period, offence data are based on the revised edition of ASOC (ASOC08) for all jurisdictions. For the 2009 reference period, offence data are based on ASOC08 for six jurisdictions (New South Wales, Victoria, South Australia, Tasmania, Northern Territory and the Australian Capital Territory). Data for Queensland and Western Australia in 2009 are based on the first edition of ASOC (ASOC97). Offence data between 2001 and 2008 are based on ASOC97. Prior to this period, offences were classified to the Australian National Classification of Offences (ANCO).
The revised classification impacts the Prisoner Census time series in relation to offence information. Prisoner numbers are not impacted. The number of offence divisions have remained the same, however changes have been made to offence subdivisions and groups resulting in some subdivisions and groups moving across divisions. Additionally, as part of the migration, some jurisdictions discovered incorrect assignment of local offence codes to ASOC, resulting in further changes to 2009 and 2010 offence data.
In 2009, the impact of the migration was measured for four jurisdictions. The largest impacts occurred in divisions 05, 11, 13 and 16 with movements greater than 15%. However, the size of these movements was largely a reflection of the small numbers within these offence categories. All other divisions were not greatly impacted.
Caution should be exercised when making comparisons to offence data prior to 2010 for Queensland and Western Australia, and comparing data prior to 2009 between migrated and non-migrated jurisdictions. National offence estimates are also impacted. For more details about these impacts, refer to Explanatory Notes paragraphs 40-45 and the Technical Note in the 2009 issue of Prisoners in Australia.