STATISTICAL AREA LEVEL 4 (SA4)
Statistical Areas Level 4 (SA4) are geographical areas built from whole Statistical Areas Level 3 (SA3s). The SA4 regions are the largest sub-State regions in the Main Structure of the Australian Statistical Geography Standard (ASGS), and have been designed for the output of a variety of regional data, including data from the 2016 Census of Population and Housing. They are specifically designed for the output of ABS Labour Force Survey data and therefore have population limits imposed by the Labour Force Survey sample. These areas represent labour markets or groups of labour markets within each State and Territory.
Whole SA4s aggregate to Greater Capital City Statistical Areas (GCCSA) and State and Territory. There are 107 SA4 regions covering the whole of Australia without gaps or overlaps. These include 18 non-spatial SA4 special purpose codes comprising Migratory–Offshore–Shipping and No Usual Address codes for each State and Territory.
The Other Territories of Jervis Bay, Cocos (Keeling) Islands, Christmas Island and Norfolk Island are together represented by a single SA4 in the 2016 ASGS.
DELIMITATION OF SA4
The SA4s were designed using a number of criteria which reflect a balance between respective considerations. Listed below are the criteria in the approximate order of importance.
A minimum of 100,000 persons was set for the SA4s, although there are some exceptions to this. In regional areas, SA4s tend to have populations closer to the minimum (100,000 - 300,000). In metropolitan areas, the SA4s tend to have larger populations (300,000 - 500,000).
Labour markets were a key consideration in the design of SA4s. The reason for this is that Labour force data has two geographic components to it - the labour supply (where people live) and demand (where people work). For statistical purposes, it is ideal to maximise the extent to which the region being analysed contains both sets of geographic locations. Labour markets are geographic regions, which reflect the highest degree of interconnectivity between the labour supply and demand. By reflecting labour markets, the output data is relevant to both labour supply and demand.
The ABS consulted with a number of experts on labour market geography and undertook analysis of the 2011 Census of Population and Housing travel to work data to identify labour markets within Australia. The resulting labour markets were characterised by a large number of very small regional labour markets, a smaller number of medium sized labour markets around regional centres, and very large labour markets representing the major metropolitan centres. While this may be an accurate reflection of Australian labour markets, many of the regions did not meet the minimum population criterion.
SA4s have also been designed to represent the labour markets of the largest regional cities such as Wollongong, Bendigo and Townsville. SA4s present specific labour force data on these cities’ labour markets.
In outer regional and remote areas labour markets tend to be small and localised around regional towns. SA4s in these areas represent aggregations of these labour markets based on geographical, social and economic similarities. SA4s which contain only remote and regional areas enable a picture of regional and remote labour force activity to be presented.
The smaller regional labour markets were amalgamated based on travel to work interactions as well as industry and regional similarities to create SA4s of approximately 100,000 to 300,000 persons. The medium sized regional centre labour markets that exceeded 100,000 persons (for example Cairns, Qld) were preserved as far as possible as SA4s that directly represent the labour market, though in some cases small closely related labour markets were included in these SA4s. The very large major metropolitan labour markets were split to reflect major employment hubs and their primary labour supply catchments. These are generally larger population SA4s of 300,000 to 500,000 persons, reflecting the fact that they represent labour markets with large populations.
Special Purpose SA4
There are non-spatial SA4s for Migratory - Offshore - Shipping and No Usual Address in each State and Territory.
The key criteria for SA4 names are that they be:
- have a maximum of 40 characters
- unique, i.e. not shared by any other SA4 in Australia.
SA4s are named according to the areas they represent:
- where a SA4 represents a labour market of a major city it is named after that city, for example:
- where a SA4 represents an employment centre within a larger city it is generally named to reflect both the larger city and the employment centre or part of the city that it represents, for example:
- Melbourne - Inner South
- Sydney - Blacktown
- where a SA4 represents a collection of labour markets in regional areas it is named using either a description of that part of the State and Territory or after one or more well-known regional areas that it closely replicates, for example:
- where this name does not identify it within Australia, it is generally preceded by the State and Territory name, for example:
- Western Australia - Wheat Belt
- Queensland - Outback.
SA4 CODING STRUCTURE
A SA4 is identified by a 3-digit hierarchical code. This comprises a 1-digit State and Territory identifier, which precedes a 2-digit SA4 identifier, which is unique within each State and Territory.
Example: 102 Central Coast
Future Allocation of SA4 Codes
In the future, it may be necessary to allocate new codes. If a SA4 is abolished, or changes significantly for new editions of the ASGS, the SA4 identifier will be retired and the replacement SA4(s) given the next available previously unused SA4 identifier within the State and Territory.
SA4 Identifier Ranges
Within each State and Territory, the SA4 identifier is in the range 01- 79. SA4 identifiers in the range 80-99 are reserved for special purpose SA4s.