Main Structure
As with previous editions, ASGS Ed. 3 will provide information about the stability and extent of change in the Main Structure between 2016 and 2021. The greatest amount of change will occur in the Mesh Block, SA1 and SA2 geographies, which are being split in areas with high population growth.

Feedback has been considered in the design process for ASGS Ed. 3. During consultation:

• 25 respondents provided specific feedback regarding ASGS boundary design
• 27 comments were received regarding more general ASGS improvements

The ABS is also addressing coastline alignment issues and undertaking an update of the Mesh Block category information. Updates are occurring to rectify issues reported by users since 2016 where this is possible within the design guidelines.

As with previous editions, the ABS will provide correspondences to help transfer data between ASGS 2016 and ASGS Ed. 3.

There are no major changes planned for SA3, SA4 or Greater Capital City Statistical Area (GCCSA) boundaries in ASGS Ed. 3. However, minor alignment shifts will occur to these boundaries as a result of alignment changes in lower level geographies. These small changes will have a minimal impact on population and as a result there will be no code or name updates.

SA4 and GCCSA boundaries represent labour markets and the functional extent of Australian capital cities respectively. They are designed with an emphasis on stability over time to support the time series of statistical releases such as the Quarterly Labour Force publication. Both SA4 and GCCSA boundaries will be reviewed for ASGS Ed. 4 to be released in 2026. There will be future consultation to assist in this process.

Coding structure
The ASGS Main Structure will use full length hierarchical codes as the primary unique identifier. The alternative short version of codes, often used for SA1 and SA2 boundaries, will no longer be provided as a primary identification key to reduce confusion created by having two different unique identifiers. Respondents to public consultation were generally supportive of this change. The ABS will provide short codes on request to support stakeholders to transition to the full length hierarchical codes. Short codes will also be stored as an attribute field in the SA1 and SA2 tables.

Naming conventions
During the design process for ASGS Ed. 3, naming conventions for SA2 boundaries have been reviewed, considering feedback from users. Full naming conventions will be outlined in ASGS Ed. 3.

Some of the changes include:

• The character limit for SA2 names will be increased from 40 to 50. This aligns with other ASGS structures.
• A number of SA2s surrounding towns called “X Region” will be revised to “X Surrounds” where the SA2 does not contain the town named. For example, the SA2 of Young is currently surrounded by a separate SA2 called Young Region which does not include the town. This SA2 will become Young Surrounds, which is a more accurate reflection of the area it refers to.