How small areas are built in Community Profile and Social Atlas.

.id builds the small areas in your Community Profile from the smallest pieces of Census geography, so they can follow the boundaries your council works to rather than the ones the Australian Bureau of Statistics (ABS) publishes. About 1,000 people is the practical minimum for an area, because below that the data becomes unreliable, partly due to ABS random adjustment to protect confidentiality of individuals (known as 'perturbation'). .id normally groups areas that fall short with their neighbours, at least at a suburb and locality level, to meet minimum population requirements.

Key concepts

Mesh Blocks

Mesh Blocks are the smallest areas the ABS defines, and in the 2021 geography most contain 30 to 60 dwellings. They're the building blocks for the ABS's larger areas, including the Statistical Area Level 1 (SA1) areas that Social Atlas maps. Social Atlas currently uses 2021 SA1s, and a 2021 SA1 has between 200 and 800 people, generally fewer in remote and regional areas. .id builds your small areas by combining a range of geographies to meet boundaries that represent logical communities used by Local Government, including splitting SA1s across boundaries and sharing out the population using dwelling counts in each Mesh Block. That is why almost any boundary can be built, including one that follows your own wards, precincts or planning areas rather than ABS suburbs, but they do need a minimum population size for this method to work.

Minimum viable population

About 1,000 people is the practical minimum for a Community Profile area, and for the areas shown on the Social Atlas analysis tab. Below that, the data becomes unreliable and the random adjustment the ABS applies to Census data to protect confidentiality (called 'perturbation without additivity') affects it heavily (see Why Census figures in .id tools can differ from the ABS website). .id can still build an area below the minimum, but treat its figures as less reliable. The minimum applies to each area on its own, so if you split an area, both parts should normally clear it. Sometimes we need to combine smaller localities with larger ones to meet this requirement, but the larger area can be created as a separate area on its own as an overlay geography.

Change over time on the same boundaries

.id normally rebuilds data from earlier Censuses on your current boundaries, so your time series describes the same ground before and after a boundary change. That's what lets you say a change you see is real and not the result of a boundary moving. Currently in Community Profile, for some topics, we can show data right back to 1991 for existing clients – that's seven Censuses on a consistent geography. New clients still go back to 2001, which is five Censuses on a consistent geography (six from 2026). The minimum population size is a trade-off for this – we need areas in each Census to have meaningful numbers based on standard areas – going back prior to 2011 involves using geographies like Census Collection Districts (CDs) instead of SA1s, and this is more difficult for smaller population places. There is an exception for areas that had close to zero population in earlier years (high growth areas). These can be recreated though they won’t show any useful information for the earlier years.

How this applies in Community Profile and Social Atlas

Community Profile covers the whole local government area (LGA), a set of small areas such as suburbs, districts, precincts or wards and, where relevant, overlay areas such as an urban and rural split, green wedge or other planning or zoning areas. The primary layer in Community Profile is known generically as 'small areas', and often represents suburbs or districts. These must cover the LGA in full without gap or overlap, and are agreed with the LGA during the build process. Other areas such as wards and precincts are termed 'overlays' and there can be multiple layers which represent parts of the same population as the primary small areas, but don’t necessarily have to cover the whole area. They can be specific sub-areas of interest, a good example of these would be activity centre boundaries in urban areas.

Social Atlas maps Census data by SA1. It can show your small area boundaries on the map overlaying the SA1s and has summary information for small areas and overlay layers on the Analysis tab.

Population Forecast has its own set of areas, which can differ from your Community Profile areas. In many cases they are the same, but forecast has a higher minimum population requirement for small areas, though it can also show more detail in some cases - for instance it can still show a high-growth area that doesn't have enough past data to appear in the profile, but will have a higher population in future.

To add, change or split an area, see How to add, change or split areas in Community Profile and Social Atlas.

Frequently asked questions

Q: Why is my suburb grouped with others?

A: The suburb is too small on its own. When an area falls below about 1,000 people, .id normally groups it with neighbouring areas. A rural area made up of several small localities can end up as one area. Decide in advance which grouping you'd accept, because it shapes every future report for that part of your LGA. This is normally workshopped with council staff when the profile is being built for an LGA, and consideration is given to demographic similarities – we try to group areas that are geographically close but also demographically similar, where grouping is required.

Q: Can you split an area that mixes different land uses?

A: Yes, when both parts should normally clear the minimum on their own. An industrial area and a residential area are often included together as it is a residential profile, and many industrial areas have close to zero population – too low to meet the minimum requirement. Due to small populations, industrial areas generally have minimal impact on the total but need to be included in the small area layer for completeness.

Q: Why can't I get Place of Work data for my custom area?

A: Place of Work and Journey to Work are two different datasets, and neither is available for custom areas. Place of Work shows where people work. It's available at LGA level (and at Work Destination Zone *DZN level in economy.id). Journey to Work shows where people travel from and to (origin by destination). We show it at LGA level only.

A DZN is an ABS geography for workplace data. It sits between an SA1 and a Statistical Area Level 2 (SA2) in size, and varies with the employment density of an area. DZNs are generally too coarse to combine into custom areas, but this may be possible on a consultancy basis. Talk to your Client Lead.

Q: What happens to suburbs that cross the LGA boundary?

A: .id cuts them at the edge of the LGA. Everything in your Community Profile relates only to the population inside your council's area, unless you've specifically asked to include areas outside. That's why an .id suburb can differ from the ABS suburb of the same name when the suburb crosses your boundary. See Why Census figures in .id tools can differ from the ABS website.

The exception to this is 'Locality Snapshots' which are available for only the latest Census year, include all localities with some basic information (no matter how small their population), and includes the whole locality where it crosses the LGA boundary.