GLOSSARY

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 population at a point in time with respect to well-defined characteristics (e.g. Persons, Manufacturing, etc.). When the word is capitalised, "Census" refers to the national Census of Population and Housing.


Centre of population

The centre of population is a measure used to describe the spatial distribution of a population. The method used to calculate centres of population in this product is based on the centroid and population of each Statistical Area Level 1 (SA1). To calculate the centre of population for an area, the latitude and longitude coordinates of the centroid of each SA1 in that area are multiplied by the SA1's estimated resident population to obtain weighted latitudes and longitudes for each SA1. These are summed to obtain a 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 Statistical Areas Level 1 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

Death is 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. This is known as the component method, and can be represented by the following equation:

P_t+1 = P_t + B - D + IM + OM

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

IM = net regional internal migration occurring between t and t+1.

OM = net regional overseas migration occurring between t and t+1.


Fastest growth

Based on the rate of change in population over a period (expressed as a percentage). See population growth rate.


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, through for example, commuting to work.


Intercensal difference

The difference between two estimates of a Census year population as at 30 June: the first based on the latest Census and the second produced by updating from the previous Census-based estimates which do not take account of information available from the latest Census.


Internal migration

The movement of people across a specified boundary within Australia involving a change in place of usual residence.


Interstate migration

The movement of people over a state or territory boundary involving a change in place of usual residence. Net interstate migration (NIM) is the difference between arrivals and 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 358,000 Mesh Blocks and they cover the whole of Australia without gaps or overlaps.


Natural increase

Excess of births over deaths.


Net overseas migration (NOM)

Net overseas migration is the net gain or loss of population through immigration to Australia and emigration from Australia. Under the current method for estimating final net overseas migration this term is based on a traveller's actual duration of stay or absence using the '12/16 month rule'. Preliminary NOM estimates are modelled on patterns of traveller behaviours observed in final NOM estimates for the same period one year earlier. NOM is:

• based on an international traveller's duration of stay being in or out of Australia for 12 months or more over a 16-month period;
• the difference between:
  • the number of 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 (NOM arrivals); and
  • the number of outgoing international travellers (Australian residents and long-term visitors to Australia) 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 (NOM departures).

NOM arrivals

NOM arrivals are all overseas arrivals that contribute to net overseas migration (NOM). It is the number of 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. Under the current method for estimating final net overseas migration this term is based on a traveller's actual duration of stay or absence using the '12/16 month rule'.


NOM departures

NOM departures are all overseas departures that contribute to net overseas migration (NOM). It is the number of 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. Under the current method for estimating final net overseas migration this term is based on a traveller's actual duration of stay or absence using the '12/16 month rule'.


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 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.


Population growth rate

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


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. Results from the PES contribute to a more accurate calculation of the estimated resident population on Census night, which is then backdated to 30 June of the Census year.


Rebasing

The 2016 Census of Population and Housing forms the base for newly compiled estimates for 30 June of the Census year, which can be compared with the alternative estimates produced by updating the 2011 Census-based estimates. Of these two estimates, the more recent Census-based estimate is assumed to be the true estimate. To overcome the break in continuity that this implies, population estimates for all years in between the two most recent Censuses are then revised. This complete exercise is known as 'rebasing', as the population estimates are compiled from a new base, 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 NOM arrivals and NOM 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.


Remoteness Structure

This structure is used to classify areas which share common characteristics of remoteness into Remoteness Areas. The degree of remoteness of each area is determined using the Accessibility/Remoteness Index of Australia (ARIA+).


Rest of state

Within each state and territory, the area not defined as being part of the Greater Capital City Statistical Area is represented by 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 Statistical Areas Level 1 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 the Section of State, Urban Centre and Localities and Remoteness Structures. SA1s are also used to approximate a number of administrative regions such as Commonwealth and State Electoral Divisions. There are approximately 57,500 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 2,300 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

Usual residence within Australia refers to that address at which the person has lived or intends to live for a total of six months or more in a given reference year. For the 30 June reference date, this refers to the calendar year around it.