GLOSSARY

Census terms, in plain English

All terms

30 terms, A to Z.

A

Area weighting (apportioning): A way to estimate figures for an area that doesn't match published boundaries, by giving it a share of each overlapping area's counts. The share can follow land area, population or dwellings, and each assumes the figure is spread evenly within what it measures.
ASGSAustralian Statistical Geography Standard: The ABS's framework of boundaries for publishing statistics, from mesh blocks of a few dozen dwellings up to states and territories, plus the ABS's versions of councils, suburbs and postcodes. It's redrawn every five years; Edition 4, released from July 2026, is the one the 2026 Census will use.

C

CALDCulturally and linguistically diverse: CALD stands for culturally and linguistically diverse, an Australian term for people born overseas (in some definitions, only in countries other than the main English-speaking ones), people who use a language other than English, or both. It has no official definition, so a CALD figure depends on which ABS variables it uses, such as country of birth, language used at home or English proficiency.
Carried figure: A count from an earlier Census moved onto newer boundaries with the ABS's population-weighted correspondences, so places can be compared across Censuses on the same map. Where a boundary didn't change, the carried figure is the ABS's own count; where it did, it's an estimate.
Catchment (trade area): The area a store, clinic, school or other site draws its customers, patients or users from. A catchment can be drawn as a ring around the site, a drive or walk time, a hand-drawn boundary, or from where existing customers live.
Census undercount and the Post Enumeration Survey: The Census undercount is the number of people the Census should have counted, less the number it did. The ABS measures it with the Post Enumeration Survey, run straight after each Census. In 2021 the net undercount was 0.7% of Australia's population, the lowest on record.
Correspondence (ABS correspondence file): A table published by the ABS for converting data from one set of geographic areas to another, such as 2021 SA2s to 2026 SA2s. Each row gives the share of a 'from' area that falls in a 'to' area, weighted by where the population lives.

E

ERPEstimated resident population: The ABS's official measure of Australia's population. It starts from the Census count, adds people the Census missed and residents who were overseas, and is updated between Censuses with births, deaths and migration.

G

G-NAFGeocoded National Address File: Australia's national index of physical addresses, each with a coordinate called a geocode, produced by Geoscape Australia from government address sources. It is released quarterly, with an open version on data.gov.au, and Geoscape's August 2026 release held about 15.9 million addresses.
GCCSAGreater Capital City Statistical Area: An ABS region representing the functional extent of a state or territory capital, taking in the towns and rural areas whose residents work, shop or socialise in the city. GCCSAs are built from whole SA4s, and Rest of State regions cover the remainder of each state.
Geocoding: Converting an address into map coordinates, so a record can be placed on a map and assigned to areas such as mesh blocks, suburbs or SA2s. Reverse geocoding goes the other way, from a point to its nearest address.

H

Household and family composition: The ABS's Census classifications of who lives together. Household composition sorts each occupied private dwelling as a family, lone person or group household. Family composition sorts each family as a couple with or without children, a one parent family or another family.
Housing stress: When a household spends more than 30% of its income on rent or mortgage repayments. A stricter definition, the 30/40 rule, only counts households in the bottom 40% of incomes, because higher earners can usually afford to spend more.

L

LGALocal Government Area: LGA stands for Local Government Area: the area a local council looks after. In ABS data, LGAs are the ABS's version of council boundaries, built from small mesh blocks so Census figures can be published for every council in Australia.

M

Median: The middle value when everything is put in order: half the values are above it and half below. Census figures for age, income, rent and mortgage repayments are published as medians because a few very large values would distort an average.
Median household income: The middle value of total household income in an area: half of households receive more and half receive less. At the 2021 Census, Australia's median household income was $1,746 a week before tax, or about $90,800 a year.
Median weekly rent: The middle weekly rent paid by households renting their home, from the Census: half pay more and half pay less. It covers renting households in occupied private dwellings, private and public, on existing as well as new leases. At the 2021 Census, Australia's median weekly rent was $375.
Mesh block: The smallest area in the ABS's boundaries, designed where possible to hold 30 to 60 dwellings and tagged with a broad land use. The ABS releases only population and dwelling counts for mesh blocks, and builds every larger area, including councils, suburbs and postcodes, from them.

P

Perturbation (small-cell adjustment): The small random adjustments the ABS makes to Census counts so that no individual can be identified. The ABS calls it introduced random error. It barely affects large counts, though it can distort very small ones, and it means table totals may not equal the sum of their parts.
Place of usual residence and place of enumeration: Two ways the ABS counts people in the Census. Place of usual residence counts people where they usually live, generally the address where they have lived or intend to live for six months or more. Place of enumeration counts them where they were on Census night.
POAPostal Area: The ABS's version of a postcode, built from mesh blocks so Census figures can be published by postcode. Postal Areas only cover postcodes where people live, so PO box and business-only postcodes aren't included.
Population density: The number of people living in an area divided by its land area, usually given as people per square kilometre. Australia as a whole has about 3.5 people per square kilometre.
Population projection: An illustration of how a population would change if stated assumptions about births, deaths and migration held. The ABS says its projections are not predictions or forecasts, and they differ from estimates, which measure a population that already exists.

R

RARemoteness Area: One of five ABS classes that group every part of Australia by its access to services: Major Cities, Inner Regional, Outer Regional, Remote and Very Remote.

S

SA1Statistical Area Level 1: The smallest area the ABS uses to publish most Census data. An SA1 is a neighbourhood block of about 400 people, usually between 200 and 800, and SA1s fit together to form SA2s.
SA2Statistical Area Level 2: A medium-sized area defined by the ABS to represent a community that interacts socially and economically. Most have between 3,000 and 25,000 residents.
SA3Statistical Area Level 3: A regional area made up of neighbouring SA2s with similar characteristics, usually home to between 30,000 and 130,000 people. SA3s are used for regional statistics and fit together to form SA4s.
SA4Statistical Area Level 4: The largest regions below state level in the ABS's main set of boundaries, built from whole SA3s. SA4s are designed to represent labour markets, and most hold between 100,000 and 500,000 people.
SALSuburbs and Localities: The ABS's approximation of officially recognised suburbs and localities, built from mesh blocks. It replaced State Suburbs (SSC) from the 2021 Census.
SEIFASocio-Economic Indexes for Areas: SEIFA is a set of four ABS indexes that rank areas of Australia by relative socio-economic advantage and disadvantage, using Census data. Each area gets a score, a rank and a decile, where decile 1 is the lowest-scoring 10% of areas and decile 10 the highest.