3238.0.55.001 - Estimates of Aboriginal and Torres Strait Islander Australians, June 2016 Quality Declaration 
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Australian Standard Geographical Structure - Main Structure, July 2016

The ABS Structures are a hierarchy of regions developed for the release of particular ABS statistics. Their components are described below:

  • Mesh Blocks (MBs): are the smallest geographical region in the ASGS. The 2016 ASGS contains 358,122 MBs covering the whole of Australia. They broadly identify land use such as: residential, commercial, agriculture and parks etc. As Mesh Blocks are very small they can be combined together to accurately approximate a large range of other statistical regions.
  • Statistical Areas Level 1 (SA1s): have been designed as the smallest unit for the release of Census data. SA1s generally have a population of 200 to 800 persons, and an average population of about 400 persons. They are built from whole Mesh Blocks, and there are 57,523 SA1s covering the whole of Australia.
  • Statistical Areas Level 2 (SA2s): are a general-purpose medium sized area built from whole SA1s. Their aim is to represent a community that interacts together socially and economically. SA2s generally have a population range of 3,000 to 25,000 persons, and have an average population of about 10,000 persons. The SA2 is the lowest level of the ASGS structure for which Estimated Resident Population (ERP), Health and Vitals and other non-Census ABS data are generally available. There are 2,310 SA2s covering the whole of Australia.
  • Statistical Areas Level 3 (SA3s): provide a standardised regional breakup of Australia. The aim of SA3s is to create a standard framework for the analysis of ABS data at the regional level through clustering groups of SA2s that have similar regional characteristics. SA3s are built from whole SA2s and in general have populations between 30,000 to 130,000. They are often the functional areas of regional cities and large urban transport and service hubs. There are 358 SA3 regions covering the whole of Australia.
  • Statistical Areas Level 4 (SA4s): are the largest sub-State regions in the Main Structure. They are designed for the output of Labour Force Survey data and reflect labour markets within each state and territory. SA4s are built from whole SA3s and cover the whole of Australia. There are 107 SA4 regions covering the whole of Australia.

For the purposes of this publication, Jervis Bay Territory, Christmas Island, Cocos (Keeling) Islands and Norfolk Island are collectively referred to as 'Other Territories' and are included in the totals for Australia. For further information see Australian Statistical Geography Standard (ASGS): Volume 1 - Main Structure and Greater Capital City Statistical Areas, July 2016 (cat. no. 1270.0.55.001).


The complete enumeration of a population or groups at a point in time with respect to well-defined characteristics (eg Population, Manufacturing, etc.). When the word is capitalised, "Census" usually refers to the national Census of Population and Housing.


A dwelling is a structure which is intended to have people live in it, and which is habitable on Census Night. Some examples of dwellings are houses, motels, flats, caravans, prisons, tents, humpies and houseboats.

There are private and non-private dwellings:
  • A private dwelling is normally a house, flat, part of a house, or even a room; but can also be a house attached to, or rooms above, shops or offices; an occupied caravan or unit in a caravan park or craft in a marina; occupied dwelling in a Manufactured Home Estate; occupied self-care unit in Accommodation for the Retired or Aged; a houseboat; or tent if it is standing on its own block of land. An occupied caravan situated on a residential allotment is also classed as a private dwelling. Private dwellings can be either occupied or unoccupied.
  • Non-private dwellings are those dwellings not included above, which provide a communal or transitory type of accommodation. They are classified according to their function. These dwellings include hotels, motels, guest houses, prisons, religious and charitable institutions, defence establishments, hospitals and other communal dwellings. Only occupied non-private dwellings are included in the Census.

Estimated resident population (ERP)

The official measure of the population of Australia, based on the concept of usual residence. It refers to all people, regardless of nationality or citizenship, who usually live in Australia, with the exception of foreign diplomatic personnel and their families. It includes usual residents who are overseas for less than 12 months out of a continuous 16 month period. It excludes overseas visitors who are in Australia for less than 12 months out of a continuous 16 month period.

Indigenous Geography Structure

Data are also presented according to the Indigenous Structure of the Australian Statistical Geography Standard (ASGS). Under this classification, areas are defined as follows:
  • Indigenous Locations (ILOCs): are aggregates of one or more SA1s. ILOCs generally represent small Aboriginal and Torres Strait Islander communities with a minimum population of 90 Aboriginal and Torres Strait Islander usual residents. An ILOC is an area designed to allow the production of Census statistics relating to Aboriginal and Torres Strait Islander people with a high level of spatial accuracy while maintaining the confidentiality of individuals. For the 2016 ASGS, 1115 ILOCs have been defined to cover the whole of geographic Australia.
  • Indigenous Areas (IAREs): are medium sized geographical units designed to facilitate the release of more detailed statistics. IAREs provide a balance between spatial resolution and increased granularity of attribute data. They are created by aggregating one or more ILOCs. For the 2016 Census, 430 IAREs are defined to cover the whole of geographic Australia.
  • Indigenous Regions (IREGs): are large geographical units loosely based on the former Aboriginal and Torres Strait Islander Commission boundaries. They are created by aggregating one or more IAREs. The greater population of IREGs enables the highest level of granularity of attribute data through greater cross classification of variables compared with IAREs and ILOCs. For the 2016 Census 58 IREGs are defined to cover the whole of geographic Australia. IREGs do not cross state or territory borders. For further information see Australian Statistical Geography Standard (ASGS): Volume 2 - Indigenous Structure, July 2016 (cat. no. 1270.0.55.002).

Indigenous status

Indigenous Status indicates whether a person identifies as being of Aboriginal and/or Torres Strait Islander origin. Indigenous status is reported (either by an individual or a person responding to a survey or Census on their behalf) in response to the question: Is the person of Aboriginal and/or Torres Strait Islander origin?

Local Government Areas (LGAs)

LGAs are an ABS approximation of official gazetted Local Government boundaries as defined by each State and Territory Local Government Department. These approximated boundaries are constructed from the allocation of one or more whole Mesh Blocks. LGAs are good for understanding the characteristics of an individual LGA at a point in time.

Median age

For any distribution the median value is that which divides the relevant population into two equal parts, half falling below the value, and half exceeding it. Thus, the median age is the age at which half the population is older and half is younger.

Net undercount

The difference between the actual Census count (including imputations) and an estimate of the number of people who should have been counted in the Census. This estimate is based on the PES conducted after each Census. For a category of person (e.g. based on age, sex and state of usual residence), net undercount is the result of Census undercount, overcount, misclassification and imputation error.

Post Enumeration Survey (PES)

The PES is a household survey conducted three to four weeks after the Census. The PES allows the ABS to estimate the number of people missed in the Census and the number counted more than once. Usually more people are missed than counted more than once in Australia, leading to a net undercount.

Relative Standard Error (RSE)

The RSE is the standard error expressed as a percentage of the estimate to which it refers, and is useful when comparing the variability of estimates of different sizes.

Remoteness Structure

The Remoteness Structure divides Australia into broad geographic regions that share common characteristics of remoteness in relation to access to services. There are six classes of RA in the Remoteness Structure: Major Cities of Australia, Inner Regional Australia, Outer Regional Australia, Remote Australia, Very Remote Australia and Migratory. Within each state/territory, each RA represents an aggregation of non-contiguous geographical areas which share common characteristics of remoteness (constructed from SA1s). While statistical data classed to this structure may be available by state/territory, characteristics of remoteness are determined in the context of Australia as a whole. Therefore, not all RAs are represented in each state/territory.
For further information see Australian Statistical Geography Standard (ASGS): Volume 5 - Remoteness Structure, July 2016 (cat. no. 1270.0.55.005).

Standard Error (SE)

A measure of the variation among the estimates from all possible samples, and thus a measure of the precision with which an estimate from a particular sample approximates the average result of all possible samples. The units of the SE are the same as the variable of interest.