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# Regional population methodology

Reference period
2021

## Estimated resident population

Estimated resident population (ERP) is the official estimate of the Australian population, which links people to a place of usual residence within Australia. Usual residence is the address at which a person considers themselves to currently live. ERP includes all people who usually live in Australia (regardless of nationality, citizenship or visa status), with the exception of people present for foreign military, consular or diplomatic reasons.

ERP, or population estimates, for Australia and it's states and territories (from now on referred to as states) are prepared quarterly and released around six months after the reference date in National, state and territory population.

Annual population estimates as at 30 June are then prepared for areas below the state level and released in this product. Estimates are prepared at the Statistical Area Level 2 and Local Government Area levels, according to the Australian Statistical Geography Standard (ASGS), and are aggregated or split to create estimates for other geographies. Population estimates are available in this product for Statistical Areas Levels 2 to 4, Greater Capital City Statistical Areas, Local Government Areas, Significant Urban Areas, Remoteness Areas, and Commonwealth and State Electoral Divisions. This is the first release of Regional population to include data on the Australian Statistical Geography Standard (ASGS) Edition 3.

This issue contains preliminary rebased estimates for 30 June 2017 to 2021 based on the 2021 Census. Age and sex breakdowns of these estimates will be released in Regional population by age and sex on 30 August 2022. Final Census-based estimates for June 2017 through to June 2021 will be released in 2023. Totals will be released in Regional population while age and sex breakdowns will be released in Regional population by age and sex

### Method

ERP as at 30 June in a Census year is calculated by adjusting Census counts of Australian usual residents to account for residents temporarily overseas, people missed or counted more than once in the Census (based on the Post Enumeration Survey), and for the births, deaths and migration that happened between 30 June and Census night.

At the national and state levels, ERP is updated from the Census base every three months by taking the population estimate at the start of the quarter and adding the components of population change: natural increase (births minus deaths), net overseas migration and (in the case of state populations) net interstate migration. This is known as the component method, and uses the demographic balancing equation:

$$P_{t+1}=P_t+B−D+NOM+NIM$$ where:

$$P_t$$ = the estimated resident population at time point $$t$$
$$P_{t+1}$$ = the estimated resident population at time point $$t+1$$
$$B$$ = the number of births occurring between $$t$$ and $$t+1$$
$$D$$ = the number of deaths occurring between $$t$$ and $$t+1$$
$$NOM$$ = net overseas migration occurring between $$t$$ and $$t+1$$
$$NIM$$ = net interstate migration occurring between $$t$$ and $$t+1$$

At the national level, net interstate migration is zero.

For Statistical Areas Level 2 (SA2s) and Local Government Areas (LGAs), population estimates are updated from the Census base annually as at 30 June also using the component method, by taking the estimate at the start of the financial year and adding natural increase and net overseas and internal (moves between and within the states) migration. The components for these sub-state areas are calculated by breaking down state-level component estimates, ensuring consistency between the state and sub-state population and component data.

The components of population change (and subsequently ERP) at the LGA level are constrained to those at the SA2 level to ensure consistency between these two geographies, based on the smallest possible regions where SA2 and LGA boundaries match in terms of the combined area containing resident population. For example, where one LGA aligns exactly with one SA2 or where a group of LGAs aligns with a group of SA2s, the components for these areas will generally match. Estimates at the SA2 and LGA level are ultimately constrained so that they add to the relevant state estimates.

Once the estimates are updated, they are scrutinised and validated by ABS analysts. Local knowledge, such as that advised by state governments is considered and used to adjust data for particular SA2s and LGAs. In some small areas, population change since the previous Census is assumed to be zero in the absence of reliable component data for these areas.

To provide an indication of ERP below the SA2 level, population estimates are calculated for Statistical Areas Level 1 (SA1s). For a Census year, SA2 estimates are apportioned across SA1s using usual residence Census counts. In intercensal years, the SA2 estimates are apportioned across SA1s by taking into account population change implied by Medicare and electoral roll counts at the SA1 level in the years following the Census. Estimates for SA1s can be aggregated to regions such as Remoteness Areas. For areas that cannot be built up from whole SA1s, such as electoral divisions and Postal Areas, Mesh Block Census counts are used to estimate the share of the SA1 population that resides in those areas. By these means, population estimates for areas other than those provided in this product (including SA1s) may be available on request via the ABS website.

### 2021 Census-based population estimates

The 2021 estimates in this release are based on the 2021 Census, with adjustments made for residents temporarily overseas, net Census undercount and overcount, and the time between Census night and 30 June. These are referred to as rebased population estimates. For more information, including the demographic adjustments made for national and state/territory ERP, see Methodology used in rebased population estimates, June 2021.

At the greater capital city and rest of state level (part of state), a further demographic adjustment was applied to account for relatively large variations in the PES net undercount adjustments between Censuses.

The following two populations were used to arrive at an adjusted 2021 rebased ERP for each part of state:

• the unadjusted 2021 rebased ERP for that part of state, and
• the 2021 unrebased ERP for that part of state (as published in Regional population, 2020-21)

A weighting of 60% was applied to the unadjusted 2021 rebased ERP split of population between the greater capital city and rest of state region for each state/territory, and 40% to the 2021 unrebased ERP split. Within each state/territory, the population for each part of state was then adjusted to arrive at this composite split (with balancing adjustments made so that the net adjustment at the state/territory level was zero), as shown in the following table.

Demographic adjustments by part of state, 2021
NSWVic.QldSAWATas.NTTotal
Greater capital city (no.)26,10028,4007,500-5002,100-60010063,100
Rest of state (no.)-26,100-28,400-7,500500-2,100600-100-63,100
Greater capital city (%)0.50.60.3-0.00.1-0.250.10.4
Rest of state (%)-0.9-1.8-0.30.1-0.40.20-0.1-0.8

ERP for all regions below each part of state was then apportioned to the new part of state ERP on a pro-rata basis. This composite method was also applied for 2016 rebasing of sub-state ERP.

### Intercensal difference

In Census years, both preliminary estimates (derived from updating ERP from the previous Census) and 'rebased' population estimates (based on the current Census) are prepared. Differences between these two sets of estimates are referred to as intercensal differences. Rebased estimates of SA2 populations for previous intercensal years are derived by apportioning the intercensal difference across the five years, while constraining to state totals. Rebased 2017 to 2020 estimates were generally derived by adding one-fifth of the 2021 intercensal difference to the previous estimate of the 2017 population, two-fifths to the previous estimate of the 2018 population, and so on. Intercensal difference was apportioned based on the unrebased growth rate for some areas (e.g. newly established areas).

As a result of the rebasing process, the components (natural increase, internal and overseas migration) published in previous issues of this product no longer sum to population change.

### Accuracy

The sub-state estimates in this product are subject to some error. Some caution should be exercised when using the estimates, especially for areas with very small population.

An indication of the accuracy of ERP can be gauged by assessing the size and direction of intercensal differences. For Australia as at 30 June 2021, the unrebased ERP over-estimated the preliminary rebased ERP by 0.2% (52,200 people). For the states and territories, the 2021 intercensal differences ranged from -5.1% (Australian Capital Territory) to +1.5% (Victoria).

To assess the quality of SA2-based estimates, unrebased estimates for 2021 were converted to SA2s based on the 2021 ASGS, and constrained to preliminary rebased state/territory ERP. These estimates were compared with preliminary rebased 2021 SA2 estimates. The average of the absolute values of the intercensal differences for these SA2 estimates (excluding areas with less than 1,000 people) was 4.1%.

The table below shows that intercensal differences were generally larger for very small areas, and lower for very large areas.

Size of SA2 (people)Number of SA2s (no.)Average absolute intercensal difference (%)
1,000 to 2,999928.9
3,000 to 4,9993064.0
5,000 to 6,9993293.7
7,000 to 9,9993974.0
10,000 to 14,9995954.3
15,000 to 19,9993843.9
20,000 and over2173.4

### Status

To meet the competing demands for accuracy and timeliness, there are several versions of sub-state population estimates. Preliminary estimates are available around nine months after the reference date with revised estimates 12 months later. Rebased and final estimates are made available after each Census, when revisions are made to the estimates for all years in the previous intercensal period.

The status of annual sub-state ERP and components changes over time, from preliminary to revised to final, as new component data becomes available at the state level. Estimates in this issue are final for 2001 to 2016 and preliminary rebased for 2017 to 2021, based on the 2021 Census.

## Components of population change

### Births and deaths

Natural increase (births minus deaths) for sub-state areas is calculated using information provided by each state/territory registry of births, deaths and marriages. The data is coded based on the place of usual residence of the mother for births, and the place of usual residence of the deceased for deaths. It is aggregated to SA2 and LGA levels and constrained to published state estimates of births and deaths.

The estimates of births and deaths in this product are prepared for financial years to correspond with the 30 June reference date for sub-state ERP. To produce timely sub-state estimates, preliminary births and deaths data are prepared using year of registration as a proxy for year of occurrence.

Preliminary births and deaths are prepared by breaking down preliminary state-level data. Later, when the state-level data is updated, the sub-state data is updated accordingly and released in the next issue of this product.

The sub-state births and deaths data in this product is not coherent with the sub-state data released in Births, Australia and Deaths, Australia which is for calendar years and has a different scope.

### Overseas migration

The movement of people from overseas to Australia's sub-state areas and vice-versa cannot be directly measured and is estimated by breaking down overseas migrant arrivals and departures at the state level to sub-state areas, using information from the most recent Census. The state-level overseas migration data is sourced from Department of Home Affairs processing systems, visa information, and incoming passenger cards, and is published in National, state and territory population.

Regional overseas migration estimate (ROME) arrivals are estimated based on counts of people who identified in the Census that they were living overseas one year ago, at SA2 level. This distribution is used to break down state arrivals each year up until the next Census. To account for changes to the distribution of overseas arrivals within a state between Censuses (e.g. in high growth areas or inner-city areas with changing numbers of temporary migrants), adjustments may be made based on up-to-date indicator data including counts of Temporary Skills Shortage visa holders and overseas students.

For ROME departures, a model distributes state-level overseas migrant departures to SA2s. This model is based on a range of information from the Census - mainly the number of people who arrived in each area from overseas in the last year. More weighting is given to areas that have high SEIFA Index of Education and Occupation scores and more than 20% of their total population born overseas. Of all the models evaluated, this model was selected as it best estimated population change between the last two Censuses. As with overseas arrivals, overseas departures may be adjusted based on additional information sources.

LGA estimates of ROME arrivals and departures are prepared by converting from SA2-level ROME arrivals and departures, using a population-weighted correspondence.

Preliminary ROME arrivals and departures are prepared by breaking down preliminary state-level data. Later, when the state-level data is updated, the sub-state data is updated accordingly and released in the next issue of this product.

### Internal migration

The movement of people between and within Australia's states and territories cannot be directly measured and is estimated using administrative data. Internal migration is estimated based on a combination of Census data (usual address one year ago), Medicare change of address data (provided by Services Australia), and Department of Defence records (for military personnel only).

Medicare is Australia's universal health insurance scheme and covers the vast majority of Australian residents. De-identified Medicare change of address counts are aggregated to SA2 and LGA levels. There are some people who are part of ERP but are not covered by Medicare, such as certain temporary visa holders. For others there is a time delay from when they move residence to when they update their address details with Medicare. To account for these issues, factors are applied to calibrate this data to internal migration data from the Census. These factors are applied by age, sex, state and move type (arrival or departure). Medicare data received for the year ending 30 September is used to estimate internal migration for the year ending 30 June. This assumes that on average the time between a person moving house and registering their change of address with Medicare is three months.

As many defence force personnel do not interact with Medicare, defence movements data is used to supplement the Medicare data. Aggregated defence force personnel movements are converted from postcode to SA2 and LGA levels. This data reflects the time of move, and is therefore not lagged.

The Medicare and defence data are combined to prepare regional internal migration estimates (RIME) at SA2 and LGA levels. Interstate RIME moves are constrained to estimates of interstate migration as published in National, state and territory population.

RIME was previously prepared and released in Migration, Australia for financial years up to 2015-16. This old series of RIME was experimental in that it was prepared independently of and is not directly comparable with ERP nor with RIME prepared for 2016-17 onwards, due to different methods and source data used. The old RIME series used Medicare change of address data aggregated to postcodes, which was converted to SA2/LGA, and was supplied to the ABS quarterly meaning that one person could record up to four moves in a financial year. RIME for 2016-17 onwards uses change of address data coded directly to ASGS areas, and is supplied and calculated on an annual basis consistent with the definition of population change over a financial year.

## Statistical geography

The Australian Statistical Geography Standard (ASGS) brings together all of the regions which the ABS and many other organisations use to collect, release and analyse geographically classified statistics. The ASGS classification structures are split into two broad groups, ABS Structures and Non-ABS Structures.

The ABS Structures are defined and maintained by the ABS, and remain unchanged for the five years between Censuses. This issue of Regional population contains data for the ABS Structures of both the 2021 ASGS (Edition 3) and 2016 ASGS (Edition 2). Further information on the ABS Structures of the 2021 ASGS (Edition 3) for which population estimates are available in this product is contained in:

Further information on the ABS Structures of the 2016 ASGS (Edition 2) for which population estimates are available in this product is contained in:

The Non-ABS Structures are not defined or maintained by the ABS, and generally represent administrative regions. As the Non-ABS Structures represent regions that are subject to ongoing change, the ABS releases updates to these Structures each year where significant change has occurred. Further information on the Non-ABS Structures of the 2021 ASGS (Edition 3) for which population estimates are available in this product is contained in:

Maps of the statistical areas defined in the ASGS are available in the online mapping tool ABS Maps.

The area figures used in this product were calculated using ABS standard Geographic Information System software from the digital boundaries of the ASGS.

## Other population measures

### Centre of population

The centre of population of a region is a point that describes a centre point of the region's population, and is calculated in this product based on SA1s. Due to the inherent imprecision in small area estimates, the centre of population should be considered indicative and not ascribed to an exact location. The use of different geographical level data in the calculation of the centre of population can result in different locations.

### Population density

The population density of each region in this product has been calculated by dividing its ERP by its area in square kilometres. The result is expressed as a number of people per square kilometre.

### Population grid

In this product, ERP is also presented in one square kilometre grid format. The population grid offers a consistently sized spatial unit and gives a refined model of population distribution, particularly for the non-urban areas of Australia. It is also an established, easy to understand and readily comparable international standard which enables users to make local, national and international comparisons of population density.

The population grid is prepared using SA1 population estimates. Within each populated SA1, all known residential dwelling locations were identified using a subset of the ABS Address Register, and the population distributed equally across the residential dwellings. The average value assigned to each dwelling was then summed within each one square kilometre grid cell across the country. This is modelled data and caution must be used in its interpretation, as the population has not been measured at the one square kilometre grid cell level.

Prior to 2021, the grid was prepared using known residential dwelling locations based on the Geocoded National Address File. The new methodology used for 2021, which makes use of the ABS Address Register, has resulted in the population grid showing a more targeted representation of the population.

The population grid is provided in ESRI Grid format and Geo TIFF format, which are recommended for users proficient in the use of Geographic Information System software.

## Confidentiality

The ABS collects statistical information under the authority of the Census and Statistics Act, 1905. This requires that statistical output shall not be published or disseminated in a manner that is likely to enable the identification of a particular person or organisation.

To guard against identification or disclosure of confidential information, a procedure is applied to confidentialise sub-state ERP and components, which are also subsequently constrained so that they add to relevant state estimates. As a result of this confidentialisation method, and forced additivity, estimates of under three people should be regarded as synthetic and only exist to ensure additivity to higher levels.

ABS statistics draw extensively on information provided freely by individuals, businesses, governments and other organisations. Their continued cooperation is very much appreciated: without it, the wide range of statistics published by the ABS would not be available. Information received by the ABS is treated in strict confidence as required by the Census and Statistics Act 1905.

## Glossary

### Show all

#### 12/16 month rule

Under a '12/16 month rule', incoming overseas travellers (who are not currently counted in the population) must be resident in Australia for a total period of 12 months or more, during the 16 month follow-up period to then be added to the estimated resident population. Similarly, those travellers departing Australia (who are currently counted in the population) must be absent from Australia for a total of 12 months or more during the 16 month follow-up period to then be subtracted from the estimated resident population.

The 12/16 month rule does not have to be continuous and takes account of those persons who may have left Australia briefly and returned, while still being resident for 12 months out of 16. Similarly, it takes account of Australians who live most of the time overseas but periodically return to Australia for short periods.

#### Australian Statistical Geography Standard (ASGS)

The ASGS brings all the regions for which the ABS publishes statistics within the one framework and has been in use for the collection and dissemination of geographically classified statistics since 1 July 2011. It is the current framework for understanding and interpreting the geographical context of statistics published by the ABS.

#### Birth

The delivery of a child, irrespective of the duration of pregnancy, who, after being born, breathes or shows any other evidence of life such as heartbeat.

#### Capital city

Refers to the Greater Capital City Statistical Areas of states and territories as defined in the Australian Statistical Geography Standard.

#### Census

The complete enumeration of a specific population at a point in time (as opposed to a survey, which enumerates a sample of the population). When the word is capitalised, "Census" refers to the national Census of Population and Housing. The Census is run by the ABS every five years and aims to count every person in Australia on Census night.

#### Centre of population

A measure used to summarise the spatial distribution of a population. To calculate the centre of population for an area in this product, the latitude and longitude coordinates of the geographic centroid of each Statistical Area Level 1 (SA1) in that area are multiplied by the population of each SA1 to obtain weighted latitudes and longitudes for each SA1. These are summed to obtain a population-weighted latitude and longitude coordinate for the area, then divided by the total population of the area to obtain a single latitude and longitude coordinate.

#### Commonwealth Electoral Division (CED)

An area legally prescribed for returning one member to the House of Representatives, Australia's Federal Lower House of Parliament. Data for CEDs are approximated by aggregating the data for Mesh Blocks that best fit the area. Where the Australian Electoral Commission revise their boundaries, CEDs are updated in conjunction with the annual update of other Non-ABS Structures in the Australian Statistical Geography Standard.

#### Death

The permanent disappearance of all evidence of life after birth has taken place. The definition excludes deaths prior to live birth. For the purposes of death registration collections compiled by the ABS, a death refers to any death which occurs in, or en route to Australia and is registered with a state or territory Registry of Births, Deaths and Marriages.

#### 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, citizenship or legal status, 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 over a 16-month period. It excludes overseas visitors who are in Australia for less than 12 months over a 16-month period. Sub-state estimates of the resident population are prepared on an annual basis by adding natural increase (the excess of births over deaths), net internal migration and net overseas migration occurring during the period to the population at the beginning of each period.

#### Greater Capital City Statistical Area (GCCSA)

Represent the socioeconomic area of each of the eight state and territory capital cities. These boundaries are built from aggregations of whole Statistical Areas Level 4. GCCSA boundaries represent a broad socioeconomic definition of each capital city, containing not only the urban area of the capital city, but also surrounding and non-urban areas where much of the population has strong links to the capital city, for example through commuting to work.

#### Highest growth rate

Based on the population change over a period as a proportion (percentage) of the population at the beginning of the period.

#### Intercensal difference

The difference between two estimates at 30 June of a Census year population: the first based on the latest Census, and the second arrived at by updating the 30 June estimate of the previous Census year with intercensal components of population change.

#### Internal migration

The movement of people across a specified boundary within Australia involving a change in place of usual residence. Net internal migration is the number of arrivals minus the number of departures and can be either positive or negative.

#### Interstate migration

The movement of people over a state or territory boundary involving a change in place of usual residence. Net interstate migration is the number of arrivals minus the number of departures and can be either positive or negative.

#### Largest growth

Based on absolute change in population over a period.

#### Local Government Area (LGA)

An ABS approximation of an officially gazetted LGA as defined by each state and territory local government department. LGAs cover incorporated areas of Australia, which are legally designated areas for which incorporated local governing bodies have responsibility. The major areas of Australia not administered by incorporated bodies are the northern parts of South Australia and all of the Australian Capital Territory and the Other Territories. These regions are identified as 'Unincorporated' in the LGA structure of the Australian Statistical Geography Standard.

#### Mesh Block

The smallest geographic region in the Australian Statistical Geography Standard (ASGS) which forms the basis for all larger regions of the ASGS. They broadly identify land use such as residential, commercial, agricultural and parks. There are approximately 368,000 Mesh Blocks and they cover the whole of Australia without gaps or overlaps.

#### Natural increase

The number of births minus the number of deaths.

#### ​​​​​​​Net overseas migration (NOM)

The net gain or loss of population through immigration to Australia and emigration from Australia.

#### Net undercount

The difference between the actual number of people who were counted in the Census (including imputations) and an estimate of the number of people who should have been counted in the Census. This estimate is based on the Post Enumeration Survey (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, differences in classification between the PES and Census, and imputation error.

#### Overseas migrant arrivals

Incoming international travellers who stay in Australia for 12 months or more over a 16-month period, who are not currently counted within the population, and are then added to the population.

#### Overseas migrant departures

Outgoing international travellers who leave Australia for 12 months or more over a 16-month period, who are currently counted within the population, and are then subtracted from the population.

#### Post Enumeration Survey (PES)

The Census Post Enumeration Survey (PES) is a household survey conducted following the Census. The PES allows the ABS to estimate the number of people missed in the Census and the number counted more than once or in error. Historically more people are missed than are counted more than once in Australia, leading to a net undercount. PES estimates of net undercount are used to adjust Census counts for use in ERP.

#### Rebasing

After each Census, the ABS uses Census counts (adjusted for undercount) to construct a new base population figure for 30 June of the Census year. Rebasing is the process of updating population estimates for the five years between Censuses, to incorporate information from the most recent Census.

#### Regional internal migration estimates (RIME)

Estimates of internal migration for Australia's sub-state areas, prepared primarily using Medicare change of address information.

#### Regional overseas migration estimates (ROME)

Estimates of overseas migration for Australia's sub-state areas, prepared by breaking down state/territory overseas migrant arrivals and departures primarily using Census information.

#### Remoteness Area (RA)

Remoteness Areas divide Australia into 5 classes of remoteness (ranging from Major Cities to Very Remote) on the basis of their relative access to services. Access to services is measured using the Accessibility and Remoteness Index of Australia (ARIA+). Within the Australian Statistical Geography Standard, each RA is created from a grouping of Statistical Areas Level 1 which have a particular degree of remoteness.

#### Rest of state

Within each state and the Northern Territory, the area not defined as being part of the greater capital city is represented by a rest of state region. The Australian Capital Territory does not have a rest of state region.

#### Significant Urban Area (SUA)

Represent individual Urban Centres or clusters of related Urban Centres with a core urban population over 10,000 people. They can also include related peri-urban areas, satellite development, the area into which the urban development is likely to expand, and nearby rural land. SUAs are aggregations of whole Statistical Areas Level 2. They do not cover the whole of Australia, and may cross state/territory borders.

#### Socio-Economic Indexes for Areas (SEIFA)

A suite of four indexes that rank areas in Australia according to relative socio-economic advantage and disadvantage. The indexes are based on the five-yearly Census of Population and Housing. The SEIFA index used in the model to distribute overseas departures within states and territories is the Index of Education and Occupation (IEO).

#### State Electoral Division (SED)

An area legally prescribed for returning one or more members to the State or Territory Lower Houses of Parliament. Data for SEDs are approximated by aggregating the data for Mesh Blocks that best fit the area. Where the Australian Electoral Commission revise their boundaries, SEDs are updated in conjunction with the annual update of other Non-ABS Structures in the Australian Statistical Geography Standard.

#### Statistical Area Level 1 (SA1)

An area defined in the Australian Statistical Geography Standard (ASGS) designed as the smallest unit for the release of Census data. They generally have a population of 200 to 800 people, and an average population of about 400 people. SA1s in remote and regional areas generally have smaller populations than those in urban areas. SA1s are used as the building blocks for a number of ASGS defined regions including Sections of State, Urban Centres and Localities and Remoteness Areas. There are approximately 61,800 SA1s and they cover the whole of Australia without gaps or overlaps. Population estimates are prepared for SA1s by breaking down estimates from the SA2 level.

#### Statistical Area Level 2 (SA2)

A medium-sized general purpose area defined in the Australian Statistical Geography Standard built from whole SA1s. Their purpose is to represent a community that interacts together socially and economically. SA2s are based on officially gazetted suburbs and localities. In urban areas, SA2s largely conform to one or more whole suburbs, while in rural areas they generally define the functional zone of a regional centre. SA2s generally have a population range of 3,000 to 25,000 people, and an average population of about 10,000 people. There are approximately 2,500 SA2s and they cover the whole of Australia without gaps or overlaps. SA2s are the base unit for preparing sub-state population estimates.

#### Statistical Area Level 3 (SA3)

An area defined in the Australian Statistical Geography Standard built up from SA2s to provide a regional breakdown of Australia. SA3s aim to create a standard framework for the analysis of ABS data at the regional level through clustering groups of whole SA2s that have similar regional characteristics. Their boundaries reflect a combination of widely recognised informal regions as well as existing administrative regions such as State Government Regions in rural areas and Local Government Areas in urban areas. SA3s generally range in population from 30,000 to 130,000 people. There are around 360 SA3s and they cover the whole of Australia without gaps or overlaps.

#### Statistical Area Level 4 (SA4)

An area defined in the Australian Statistical Geography Standard designed for the output of labour force data and to reflect labour markets. In rural areas SA4s generally represent aggregations of multiple small labour markets with socioeconomic connections or similar industry characteristics. Large regional city labour markets are generally defined by a single SA4. Within major metropolitan labour markets SA4s represent sub-labour markets. SA4s are built from whole SA3s. They generally have a population of over 100,000 people to enable accurate labour force survey data to be generated. There are 107 SA4s and they cover the whole of Australia without gaps or overlaps.

#### Urban Centre and Locality (UCL)

Aggregations of Statistical Areas Level 1 which represent population centres with populations exceeding 200 persons. Centres with a core urban population of 1,000 persons or more are considered to be Urban Centres, whilst smaller centres with populations of between 200 and 999 people are considered to be Localities.

#### Usual residence

Within Australia, usual residence is the address of the dwelling at which a person considers themselves to currently live, either having lived there for some time or intending to live there for some time.

## Abbreviations

### Show all

 ABS Australian Bureau of Statistics ACT Australian Capital Territory ASGS Australian Statistical Geography Standard CED Commonwealth Electoral Division Census Census of Population and Housing ERP estimated resident population GCCSA Greater Capital City Statistical Area LGA Local Government Area no. number NOM net overseas migration NSW New South Wales NT Northern Territory PES Census Post Enumeration Survey Qld Queensland RA Remoteness Area RIME regional internal migration estimates ROME regional overseas migration estimates sq km square kilometre S/T state or territory SA South Australia SA1 Statistical Area Level 1 SA2 Statistical Area Level 2 SA3 Statistical Area Level 3 SA4 Statistical Area Level 4 SED State Electoral Division SEIFA Socio-Economic Indexes for Areas SUA Significant Urban Area Tas. Tasmania Vic. Victoria WA Western Australia