National Offence Index (NOI)

The National Offence Index (NOI) is a tool which provides an ordinal ranking of the offence groups in the Australian and New Zealand Standard Offence Classification (ANZSOC) according to perceived seriousness, from most to least serious. 

The purpose of the NOI is to enable the representation of an individual offender, defendant, or person in custody by a single offence where they have multiple criminal offences. Where an offender has two or more offences that are classified to different categories of the ANZSOC, a principal (or most serious) offence can be selected using the higher ranking in the NOI.

For example, where an offender has two offences (0611 Aggravated burglary of a dwelling and 0941 Unlawful possession of drugs), the principal offence would be aggravated burglary of a dwelling due to this offence having a higher ranking in the NOI (82 vs 179). 

The first edition of the NOI was published in 2003. The ABS developed the initial NOI by building on the 1998 version of the Offence Seriousness Index developed by the Crime Research Centre in Western Australia, using sentence data from the 2001-02 Higher Criminal Courts collection to refine the ordering by seriousness (see Appendix 5 in Criminal Courts, Australia, 2001-02). 

The NOI was updated to incorporate the release of the Australian Standard Offence Classification (ASOC) with a second edition released in 2009. The third edition of the NOI, published in 2018, assigned rankings to the remaining supplementary offence codes of the ANZSOC that were previously unranked.

This fourth edition of the NOI (2024) incorporates the fourth edition of the ANZSOC (2023) to ensure the continued compatibility between the ANZSOC and the NOI. For the most part, group codes that had a one-to-one match between ANZSOC 2011 and ANZSOC 2023 have remained similarly ranked, with adjustments to accommodate the additional 54 offence groups that were added to the ANZSOC 2023. New group codes have largely been added to rankings alongside similar codes within the same division, with consideration given to their sentencing outcomes.

As with earlier editions, the latest review of the offence group rankings to produce the NOI 2024 incorporated consultation with crime and justice stakeholders to reflect a more contemporary view of the perceived seriousness of crimes.  

Following the principles used in the previous editions of the NOI, supplementary ‘nfd’ (not further defined) codes have been inserted directly under the lowest ranked associated group (or subdivision) code, so some may have moved relationally lower in the NOI 2024 due to altered inclusions to subdivisions or divisions in ANZSOC 2023.

The 2024 National Offence Index is available in Downloads.