Census explained

The 2026 Census of Population and Housing will be Australia’s 19th Census.

The 2026 Census will build on what was learnt in delivering the 2021 Census. The 2026 Census will be designed so that it can continue to:

• achieve high quality Census data at a national, state and small area level to inform decisions so that the right services can be provided across Australia
• maintain the value of the Census for all Australians
• deliver a safe Census with a good public experience. 

We are already planning how we will design the 2026 Census, including the consultation and testing we need to undertake so we can be sure the design will meet our objectives.

We will continue working closely with Census stakeholders, including data users and Aboriginal and Torres Strait Islander and culturally and linguistically diverse (CALD) communities. Connecting and seeking guidance from these communities helps us understand their needs so we can provide the right support; where, when and how it’s needed.

While paper materials will still be available, the 2026 Census will take a digital first approach. Technology changes rapidly and we will continue to evolve to ensure a safe, secure and easy online Census experience.

The 2026 Census will also take a ‘Privacy by design’ and ‘Security by design’ approach. When setting up new systems and processes, the Australian Bureau of Statistics (ABS) ensures that good privacy practices are built into the design specifications. A critical part of privacy by design is understanding privacy impacts on individuals. Privacy impact assessments provide the framework for managing, minimising or removing privacy impacts.

Security by design is an approach the ABS takes to develop its IT systems. Continuous testing occurs at every stage of development and deployment to ensure best practices are followed. Taking this approach focuses on making systems free of vulnerabilities and resistant to attacks.

For the first time, the Australian Bureau of Statistics (ABS) is partnering with Services Australia to introduce a new option to subscribe to get updates and access the 2026 Census through myGov. 

In 2023, a myGov user audit identified new services and features for myGov that should be considered to increase the value provided by myGov to Australians. This included a recommendation to introduce myGov as a new pathway to access the Census online form.

myGov is being introduced to provide another option to access the Census online and will be just one of the ways people can complete the Census in 2026. 

Personal information will not pre-filled when accessing the Census through myGov, as there is no connection with other government agencies. The personal information provided to the ABS in the Census is confidential. 

Before the 2026 Census, we will be testing the myGov pathway as part of the upcoming Census Test on 5 August 2025.

From mid July 2025, users can subscribe to get Census Test updates through myGov. Users will need to enter the address that they will be staying at on 5 August 2025.

People who subscribe to Census Test updates through myGov will get a message sent to their myGov Inbox when it’s time to complete the Census Test. The link in the Inbox message will allow people to complete the Census Test online on behalf of their household.

Census Test participants who receive a letter or paper form and have subscribed through myGov can complete it in their preferred way. 

After the Census Test, users will have the opportunity to provide feedback on their experience. Users will be automatically unsubscribed after the Census Test and more information will be available about how to subscribe to the 2026 Census. 

More information can be found at www.census.abs.gov.au/about/mygov.

Since the first National Census in 1911, topics have been added, removed and changed on the Census form to reflect contemporary views and emerging information needs. This ensures Census data remains relevant in supporting key decisions and adds value to the economic, social and cultural make-up of the country.  

To add new or enhanced topics, the ABS considers the national importance of the data, its availability on other datasets and also ensures the Census is not a burden to complete. 

In 2023, the ABS undertook a two-phase consultation process on what topics to include, remove or change for the 2026 Census. The outcomes of the public consultation process have been published on the ABS website.

The ABS commenced testing a shortlist of potential content changes in late 2023. The ABS used a set of criteria to determine this shortlist. In mid-2024, after reviewing testing outcomes and engaging with key stakeholders, the ABS recommended to the Australian Government that gender and sexual orientation data be collected in the 2026 Census.  

The ABS also recommended the Government remove the Number of children ever born topic from the 2026 Census, with the intention to include this topic again in 2031. Main language other than English used at home and Proficiency in spoken English topics will have updated wording to be more inclusive of sign language users.

On 8 September 2024, Assistant Minister Leigh announced that the Government had decided to include a new topic of 'sexual orientation and gender' in the 2026 Census, for people aged 16 years and older. The Government also accepted the ABS recommendation to remove the Number of children ever born topic and the other minor wording updates. 

The new topic is now included in the Census and Statistics Regulation 2016.

The ABS has published the final questions for the 2026 Census on the ABS website. 

The 2021 Census marks 50 years of Aboriginal and Torres Strait Islander peoples being fully included in the Census. This followed the 1967 Referendum, where over 90 per cent of Australians voted to include all Aboriginal and Torres Strait Islander people in official estimates of the Australian population. This amendment to the Australian Constitution was a significant milestone in the history of Australia and for the Australian Bureau of Statistics (ABS).

Indigenous status

The 2021 Census asked if a person is of Aboriginal and/or Torres Strait Islander origin. This provides data on Indigenous Status and relates to a person’s Australian Aboriginal and/or Torres Strait Islander descent, and for some people, their cultural identity. It is the basis of Australia’s official Aboriginal and Torres Strait Islander population estimates.

Ancestry

Ancestry relates to the place a person, or their parents or grandparents, were born or the cultural group they most identify with. People could provide up to two responses to the ancestry question.

The 2021 Census included new mark boxes for Aboriginal and Torres Strait Islander ancestries on the Census form to increase its inclusiveness and usability for Aboriginal and Torres Strait Islander people. These improvements were also intended to increase awareness of the Aboriginal and Torres Strait Islander ancestries as available response options. For people completing the Census online and who identified as Aboriginal and/or Torres Strait Islander, the new mark box response categories were displayed at the top of the list.

The ancestry question can be complex to answer:

• People who identify as being of Aboriginal and/or Torres Strait Islander origin may or may not select Aboriginal and/or Torres Strait Islander as their ancestry.
• People who do not identify as being of Aboriginal and/or Torres Strait Islander origin may select Aboriginal and/or Torres Strait Islander as their ancestry.
• People may answer the question on behalf of others, for example a parent or guardian completing the Census form on behalf of their child/children.

Due to the changes to the ancestry response categories in the 2021 Census, there was a significant increase in people selecting an Aboriginal and/or Torres Strait Islander ancestry. As a result, Aboriginal and Torres Strait Islander ancestry data from the 2021 Census is not directly comparable with previous censuses.

Language

The 2021 Census asked, ‘Does the person use a language other than English at home?’. The supporting information for this question advised people to include the use of Aboriginal and Torres Strait Islander languages.  

An enhancement to the online form presented a check box for Aboriginal and/or Torres Strait Islander language for those respondents who identified as Aboriginal and/or Torres Strait Islander in the Indigenous status question. To improve the data collected on Aboriginal and Torres Strait Islander languages, the person also had the option of specifying the language.

Census collection process

ABS used targeted recruitment strategies to increase the proportion of Aboriginal and Torres Strait Islander people working as field staff for the 2021 Census.

Community Field Officers (CFOs) were recruited in large numbers to interview households in remote discrete communities. They also worked in urban areas.

In cities and regional towns, Census staff worked with Aboriginal and Torres Strait Islander organisations to provide additional direct support through fill-in-form sessions, pop-up hubs and doorstep assistance.

In remote areas, the Census was conducted over an extended period between July and August to allow remote teams more time to cover vast areas and visit multiple communities. COVID-19 protocols were followed, having been shaped through consultation with communities, land councils and Aboriginal Community Controlled Health Organisations (ACCHO).

Advertising was tailored for Aboriginal and Torres Strait Islander audiences and included media placement in Indigenous press, radio and television. Radio advertising was translated into 19 Indigenous languages.

Undercount

Aboriginal and/or Torres Strait Islander undercount is estimated by the Post Enumeration Survey conducted after each Census. For the 2021 Census, the Aboriginal and Torres Strait Islander population net undercount was 17 per cent. This is a similar level of undercount as in 2016. 

Improving the undercount will continue to be a key focus for planning the 2026 Census.

Further resources

• Aboriginal and Torres Strait Islander people topic page
• Aboriginal and Torre Strait Islander ancestries
• Indigenous Status standard
• Aboriginal and Torres Strait Islander Peoples statistics
• Census dictionary

Ancestry measures a place or cultural group often related to where a person’s parents or grandparents were born. The aim of this question on the Census is to better understand a person’s background and can help identify distinct cultural groups within Australia. When ancestry data is used alongside birthplace, language and religion, and country of birth of parents, it provides an indication of the ethnic background of first and second generation Australians.

To help people determine their ancestry, the Census form included advice for people to consider the origins of their parents and grandparents. Up to two ancestries could be selected. If someone were to provide more than two ancestries, only the first two were processed. As this question provides the option for multiple responses, the total count of responses for all ancestries in Australia exceeds Australia’s total population.

In 2021, the examples provided for ‘other ancestries’, and the order of response categories was updated based on the 2016 Census results.

For the first time, the 2021 Census included new mark boxes for Aboriginal and Torres Strait Islander ancestries. For people completing the Census online and who identified as Aboriginal and/or Torres Strait Islander, these response categories were displayed at the top of the list. In the 2021 Census, there was a significant increase in people selecting an Aboriginal and/or Torres Strait Islander ancestry.

The Australian Standard Classification of Cultural and Ethnic Groups (ASCCEG) is the Australian statistical standard for classifying cultural and ethnic groups. Use of the ASCCEG by statistical, administrative, and service delivery agencies improves the comparability and compatibility of data about ethnicity collected from different sources.

Access Census data related to ancestry from the Cultural and Linguistically Diverse topics page.

Further resources

• Census Dictionary
• Ancestry Standard

In the lead up to the 2021 Census, stakeholders identified veterans as a vulnerable group with specific health and care needs.  

While records exist for current Australian Defence Force (ADF) personnel, they are not maintained for former service and limited historical data on service personnel is available.

Collecting information about service with the ADF will provide a better understanding of the circumstances of Australia’s veteran community to enable better outcomes. This could include assistance with well-being issues such as employment outcomes post-separation, homelessness and the challenges faced by families of veterans.

For these reasons, the 2021 Census included the question ‘Has the person ever served in the Australian Defence Force?’ for the first time. If the person responded yes, they could select Regular or Reserves service and either current or previous service.

Current service

Current service includes those who, at the time of the 2021 Census were aged 15-64 years and were part of the:

• Australian Army (including NORFORCE (North-West Mobile Force))
• Royal Australian Navy
• Royal Australian Air Force

A current ADF service member may be engaged in:

• Regular service: considered a person’s main ongoing job, with most roles full-time in nature. They may have also engaged in Reserves service previously.
• Reserves service: normally part-time in nature and can include up to 200 days of service per year, depending on the role. They may have also engaged in Regular services previously.

Previous service

Previous (former) service includes former ADF members aged 15 years and over who served in Regular or Reserve services (including the National Service and the Second Australian Imperial Force) who are not currently serving in the ADF.

Further resources

• Service with the Australian Defence Force topic page
• Census dictionary

The Census helps build a picture of educational attainment and qualifications across Australia. Census questions about educational attainment and qualifications are asked of people aged 15 years and over. Data from these questions can be used to:

• understand changes in Australia over time
• determine the general level of educational achievement of the Australian population
• show how different groups of people take part in education
• investigate the relationship between levels of education and employment outcomes, income and other socioeconomic variables
• help to plan education services in different areas.

Questions regarding educational qualifications in general have been asked on every Census since 1911. Level of highest educational attainment was first reported in 2006.

Questions include the highest level of primary or secondary school a person has completed, and if a person has completed any educational qualification. The Census then asks about the highest level of qualification a person has obtained and the main field of study of that qualification.

Non-school qualifications

Non-school qualifications refer to educational attainments other than those of a pre-primary, primary or secondary education level.

Census data will only reflect the highest level of non-school qualification obtained; meaning if a person has a graduate diploma and bachelor degree only the graduate diploma will be recorded.

Non-school qualification levels:

• Postgraduate degree
• Graduate diploma and graduate certificate
• Bachelor degree
• Advanced diploma and diploma
• Certificate

While most non-school qualifications are of a higher level than school qualifications, in some cases secondary education is regarded as higher than some certificate level attainments. For instance, completing year 10, 11 or 12 at school is a higher educational attainment than a certificate I or II.

Further resources

• Census dictionary - Level of highest educational attainment (HEAP)
• Census dictionary - Non-school qualification (QALLP)
• Australian Standard Classification of Education (ASCED)

Census question design

The 2021 Census contained a new question on long-term health conditions. Data from this question can be used to inform preventative health programs, plan for community services and assist decision-making by researchers, policy makers, and educators.

The 2021 Census included the question ‘Has the person been told by a doctor or nurse that they have any of these long-term health conditions?’ for the first time. Accompanying information for the question advised respondents to include health conditions that have lasted, or are expected to last, for six months or more. Respondents were also asked to include health conditions that may recur from time to time, or are controlled by medication, or are in remission.

The list of conditions were chosen based on outcomes of stakeholder consultation, how common they are, and how the data collected can inform services, policy, and research. The list included:

• Arthritis
• Asthma
• Cancer (including remission)
• Dementia (including Alzheimer’s)
• Diabetes (excluding gestational diabetes)
• Heart disease (including heart attack or angina)
• Kidney disease
• Lung condition (including chronic obstructive pulmonary disease (COPD) or emphysema)
• Mental health condition (including depression or anxiety)
• Stroke
• Any other long-term health condition(s)
• No long-term health condition.

Census allows for the analysis of long-term health conditions data at detailed geographic and sub-population levels, such as below state and territory level or by country of birth.

National prevalence measures

The National Health Survey (NHS) and the National Aboriginal and Torres Strait Islander Health Survey (NATSIHS) are recommended resources for national and state/territory level prevalence measures relating to long-term health conditions, except for mental disorders. The National Study of Mental Health and Wellbeing (NSMHWB) is the recommended source for information on mental disorders.

National Health Survey (NHS)

The NHS is an in-depth survey conducted by interview (except in 2020-21, which was conducted via a self-report webform due to the COVID-19 pandemic). It provides prevalence rates at the national and state/territory level about health status of the population. It includes long-term health conditions and health risk factors such as smoking, Body Mass Index, diet, exercise and alcohol consumption.

National Aboriginal and Torres Strait Islander Health Survey (NATSIHS)

NATSIHS provides information about long-term health conditions, as well as disability, lifestyle factors and use of health services. It enables the monitoring of trends in the health of the Aboriginal and Torres Strait Islander population over time.

National Study of Mental Health and Wellbeing (NSMHW)

The NSMHW forms part of the Intergenerational Health and Mental Health Study (IHMHS). It aims to help understand the mental health of Australians, including their use of services and their social and economic circumstances. It is the recommended source for prevalence data for mental disorders.

Further resources

• Health topic page
• Comparing long-term health conditions data in Census with NHS and other sources
• Census dictionary
• National Health Survey
• National Aboriginal and Torres Strait Islander Health Survey
• National Study of Mental Health and Wellbeing

A question on sex has been included in every Australian Census since 1911. The sex question is one of the most important in the Census. Along with age and location, it directly feeds into the official estimates of Australia’s population.

The ABS defines a person’s sex as being based upon their sex characteristics, such as their chromosomes, hormones, and reproductive organs.

For the first time, the 2021 Census allowed all respondents to select from three response options for the sex question: male, female, and non-binary sex. The purpose of this change was to allow respondents to participate in the Census when the male and female sex categories did not accurately describe their sex.

Following prior consultation, the ABS communicated at the time of the 2021 Census that data output from the sex question in most Census data releases will be reported as male and female only. The intention is to minimise misinterpretation of this data.

Where a person provided a male or female response in combination with a non-binary sex response, the male or female response was used to assign a binary sex value. In cases where only non-binary sex was selected, sex was derived in our statistical processes using random allocation. This process was designed following consultation, including representative bodies from the LGBTIQ+ communities, and consideration of the statistical uses of the Census.

Information on the non-binary sex responses will be released in an analytical article in September 2022 that will include analysis on the write-in responses and provide appropriate supporting explanatory materials.

Allowing respondents to report a sex outside of male or female binary options has been an evolution for the Census. In the 2016 Census, people were required to follow special procedures to request an online form in order to report a sex other than male or female. Prior to 2016, it was only possible to report male or female on the Census form. Gender identity, variations of sex characteristics and sexual orientation were not asked on the 2021 Census. Information that is collected on the Census is outlined in the Census and Statistics Regulation 2016, which is part of the Census and Statistics Act, 1905. The topics that are included on the regulation, and therefore collected on the Census, are decided by the Australian Parliament. The regulation specifies that the Census should collect data on sex.

The number of people who reported a sex of non-binary on the 2021 Census cannot be used as a measure of gender diversity, non-binary gender, or transgender communities. Gender is being collected in some ABS surveys that are currently or soon to be in the field, including the suite of surveys included in the Intergenerational Mental Health and Health Surveys.

In 2023, the ABS will be reviewing the information to be collected in the 2026 Census.

Further resources

• Media statement
• Non-binary sex article
• Census dictionary
• The National Study of Mental Health and Wellbeing, and the Survey of Disability, Ageing and Carers collect information on gender.
• Standard for Sex, Gender, Variations of Sex Characteristics and Sexual Orientation Variables

The Census in Australia counts people where they are staying on Census night. This is known as ‘place of enumeration’. This means people complete the form at that address even if they are travelling or staying temporarily with others.

The Census form also asks questions about where the person usually lives, known as the ‘place of usual residence’. ‘Place of usual residence’ refers to the address where a person has lived or intends to live for six months or more.

The ‘place of usual residence’ data is the information that informs Australia’s official population count (Estimated Resident Population).

One of the reasons for having Census night mid-week in August is to minimise the impact of travel, by avoiding major public holidays and school holidays to make it simpler for people to complete.

COVID-19

During the collection period for the Census, much of the eastern seaboard was under lockdown and travel was significantly restricted between and within states. Some population groups may have been more affected by COVID-19 restrictions than others. For example, counts of transitory populations such as agricultural employees and tourists may be different in some areas compared to Census data in previous years.

Away from home on Census night

Up to three people who were away from home could be recorded on the Census form for that household. The information we collect for people who were away from home on Census night includes:

• Age
• Sex
• Aboriginal and/or Torres Strait Islander origin
• Relationship to Person One/Person Two
• Full-Time/Part-Time Student Status.

We use this basic information to determine the structure of a household. For example, whether it is made up of families or people who are unrelated.

Scope of the Census

Not only does the Census count all people, but it also counts all dwellings. This includes private dwellings such as houses and apartments, as well as non-private dwellings such as hospitals, nursing homes, hotels and motels.

The only exclusions from the Census counts are diplomats and their families, diplomatic dwellings, and visitors from overseas who are not required to undergo migration formalities such as foreign crews on ships.

Further resources

• Topic page
• Comparing Place of usual residence with Place of enumeration
• Temporarily Absent People – why this data is collected
• Census dictionary

A person’s religious affiliation is asked on the Census as part of a set of questions on cultural diversity and has been collected since the first national Census in 1911. The question aims to measure religious affiliation; it does not ask about how a person practices their beliefs e.g., praying or going to a church or temple.

The religious question is voluntary due to the provision in the Constitution that states that the Commonwealth is not to legislate in respect of religion. Therefore, people cannot be required to answer this question.

Based on the most common responses from the 2016 Census, the top ten religions, including ‘no religion’ had a tick box listing on the 2021 Census form. A text field was provided to capture other responses not listed. The question allowed people to respond with secular or spiritual beliefs and to indicate if they have no religious affiliation.

Whether a person selected from a tick box or wrote in an 'other' religious affiliation, all responses are classified according to the Australian Standard Classification of Religious Groups (ASCRG). The classification has seven broad groups made up of 131 detailed religious groups:

• Buddhism
• Christianity
• Hinduism
• Islam
• Judaism
• Other religions inc. Australian Aboriginal Traditional Religions, Chinese Religions and Japanese Religions
• Secular Beliefs and Other Spiritual Beliefs and No Religious Affiliation

The ‘Secular Beliefs, and Other Spiritual Beliefs and No Religious Affiliation’ broad group is where responses like Jedi and Pastafarianism are included.

Data on religion can be used for policy and to plan for educational facilities and church buildings, aged persons' care facilities and services. It may also be used in research, and in assigning chaplains and other care providers to hospitals, prisons, armed services, universities, and other institutions. Data can also be used to determine the allocation of time to community groups on public radio and in other media.

Further resources

• Cultural diversity topic page
• Census Dictionary

Our extensive consultation on Census topics determined that the question on home internet access did not provide a contemporary reflection of today’s society with the increase in mobile internet usage on personal devices outside of the home.

The Survey of Education and Work provides annual information on a range of key indicators of educational participation and attainment of people aged 15-74 years. Information is also collected on current engagement in education and work.

The survey is conducted as a supplement to the monthly Labour Force Survey. The annual time series allows for ongoing monitoring of the level of education of Australia's population including:

• current and previous study 
• type of educational institution attended 
• highest year of school completed 
• level and field of highest non-school qualification 
• engagement in education and work, and
• selected characteristics of apprentices and trainees.

The 2021 Census asked questions including status in the labour force, occupation, industry of employment, level of non-school qualification and field of study for people aged 15 years and over. Data from the Census also indicates whether a person is engaged in work and/or study, and the extent of that engagement.

The Census provides a rich snapshot of all people living in Australia on Census night. It is the leading source of information for small population groups and areas and helps build a picture of educational levels in each area of Australia. The Census also collects information about a range of characteristics of people, including, but not limited to, their labour force status, enabling analysis across a broader range of socioeconomic dimensions.

Further resources

• Survey of Education and Work
• Education and Work, Australia methodology

The ABS collects information on the labour market activity of people aged 15 years and over. This information is collected both as part of the Census of Population and Housing (Census) and the Labour Force Survey (LFS). The statistics produced in these collections are not directly comparable as there are a number of differences in how, when and what data is collected.

The LFS produces the most authoritative estimates of labour market information, including employment, unemployment and underemployment. It measures changes over time in the Australian labour force and provides a high-quality measure for use in international comparisons. The LFS provides a highly accurate estimate of key labour force statistics of the Australian economy and is the leading source of data for monitoring Australia’s labour market conditions. Labour force statistics are published monthly by the ABS.  

The Census provides a rich snapshot of all people living in Australia on Census night. It is the leading source of information for small population groups and areas, and allows for the analysis of labour market activities, industry and occupation data at a detailed level. The Census also collects information about a range of characteristics of people, including, but not limited to, their labour force status, enabling analysis across a broader range of socioeconomic dimensions.

COVID-19 impacts on labour market data

COVID-19 lockdowns were in place on Census night (10 August 2021), as well as in the weeks before and after the Census. This has impacted data on a range of labour market indicators, such as the number of people working from home, the number of hours worked and whether someone considered themselves to be employed or unemployed during lockdown conditions.

As the Census is a self-completed form, a person’s response may differ between the Census and the LFS. In the LFS, highly trained interviewers assist the person to complete the form and ask a range of questions to determine if someone was employed. Complexities in interpretation of employment during lockdown, and the level of uncertainty and pace of change at the time could cause differences in responses between the Census and LFS.

Further resources

• Information paper - Comparing the 2021 Census and the Labour Force Survey

The Census provides a contemporary picture of Australian society every five years. As the Census is collected from the entire population in Australia, it is a critical source of information for understanding small areas and small population groups. Housing affordability is of interest to the Australian public and can be used for policy, research and understanding changes over time. The 2021 Census provides a rent affordability indicator and mortgage affordability indicator that is comparable across geographies. 

The affordability indicators are a ratio that compare rental/mortgage payments and household income. The Census data used to calculate the ratio includes:

• the tenure type of the dwelling
• total payment by the household for the dwelling
• total income persons usually receive in a household.

The ratio is presented as renter households/owner with mortgage households:

• where payments are less than or equal to 30 per cent of household income
• where payments are greater than 30 per cent of household income
• unable to determine (includes households where rent, mortgage or income were not stated, or partially stated). 

The affordability indicators are new Census variables and should not be compared to historical QuickStats.

Rent payments

The Census collects information on rent payments for responding dwellings that are rented. The data is collected in a single dollar amount. The rental affordability indicator excludes dwellings that are occupied rent free. Rent payments greater than 30 per cent of income may not necessarily indicate affordability for the household as households may be supported through other means, for example savings or wealth.

Mortgage repayments

The Census collects information on mortgage repayments for dwellings that are owned with a mortgage. Mortgage payments are often a large component of housing cost. Households with mortgage payments greater than 30 per cent of income may not be an indicator of affordability for several reasons, including:

• The point-in-time collection may cover a period where principal loan repayments or interest-only loan repayments were being made.
• Some households choose to pay more than the minimum required payment to pay off a mortgage faster.

Income

Income is a complex concept and entails some subjectivity, such as the inclusion of superannuation and dividends. The Census collects the income ranges of each person in the household aged 15 years or over. To sum these personal income values to calculate a household income, a specific dollar amount is allocated to each person. A median dollar value for each range, derived using data from the Survey of Income and Housing, is used for this purpose. For more information, see the Survey of Income and Housing, User Guide.

Advantages

The main advantages of Census data on affordability indicators are:

• it includes the total Australian population, as opposed to surveys which are based on a sample of the total population. This means the data can be analysed by smaller geographic regions or small population groups.
• the data can be cross-tabulated with other data collected in the Census.

Limitations

The main limitations of Census data on affordability indicators are:

• data relies on the respondent self-reporting rent and mortgage payments on a weekly, fortnightly or monthly basis
• data relies on the respondent self-reporting income on a per week or per year basis
• data on income is only available as an income range
• under-reporting may occur due to self-reporting and reporting on behalf of other members of the household.

COVID-19 impact

At the time that the 2021 Census was conducted on 10 August 2021, many states and territories introduced programs to provide assistance for tenants impacted by COVID-19. Similarly, during this time, some banks offered mortgage relief. These options may have impacted on responses to the question on the Census form about how much the household pays for the dwelling.

Data analysis

When Census indicators are presented as an aggregate for all households, trends in certain income brackets may not be visible. 

Generally, analysis on affordability focuses on lower income households. The ability to pay for other living costs is more likely to be adversely affected when spending more than 30 per cent of income on housing costs, compared to higher income households. In the public domain, this has often been referred to as financial stress.

Other ABS surveys

The ABS Survey of Income and Housing (SIH) has collected detailed information on income, household net worth, housing, household and personal characteristics every two years. It is used to analyse and monitor the social and economic welfare of Australian residents in private dwellings. Data from the SIH includes other rental and mortgage affordability indicators that are not subject to the same limitations as Census indicators.  

The ABS is releasing data from the 2021 Census in three phases:

• in June 2022, key demographic, cultural diversity and health data was released
• in October 2022, employment, educational qualifications and internal migration data will be released
• in early to mid-2023, complex data such as distance to work, socio-economic indexes for areas (SEIFA) and counts for people experiencing homelessness will be released.

All information collected in the Census is confidential, and no identifiable information can be released.

The 2021 Census topics and data release plan is published on the ABS website.

Statistics from the 2021 Census will be released in the same core products as previous Censuses, including through QuickStats, Community Profiles, TableBuilder and DataPacks & GeoPackages.

The Census of Population and Housing (the Census) counts every person and every dwelling in Australia on Census night. Australia’s 18th Census night occurred on Tuesday 10 August 2021.

The Census response rate is based on the number of private dwellings that returned a completed form as a proportion of all private dwellings occupied on Census night.

The response rate is an official completion measure for the Census, and an important way to understand data quality. Delivering a very high response rate will help to ensure the data is of high quality.

The ABS monitored the number of forms submitted during Census collection and provided additional support where it was needed most to ensure everyone in Australia had the opportunity to participate in the Census.

The collection of data commenced before Census night and continued for several weeks after Census night to help achieve a high level of participation. Households that did not respond were mailed a reminder to participate. Census staff also followed up with dwellings that did not complete a Census form.

During the Census collection, the ABS released a national tally of forms received online and by paper as an indicator of participation. A regular breakdown of tallies for each state and territory was published until the online form closed on 1 October 2021.

The final response rate is only available after scanning, processing and quality assurance of all Census forms is complete.

Australia’s Census has historically achieved a very high response with response rates over 95 per cent.

The official 2021 Census response rate will be published with the first release of Census data on 28 June 2022 with a breakdown of online and paper form responses. Increased online completion will provide higher quality Census data.

The Census includes everyone in Australia, Norfolk Island, the Territories of Cocos (Keeling) Islands and Christmas Island. This includes international visitors and students.

Although the Census is compulsory, the ABS relies on the goodwill of the Australian community to complete their Census. The Census is conducted under the authority of the Census and Statistics Act 1905 (the Act). This Act gives the Australian Statistician the authority to request people to complete the Census form.

Under the Act, if someone refuses to participate in the Census, the Australian Statistician can direct them to complete a form through a formal written notice. If someone continues to refuse after being directed by the Australian Statistician, they can be prosecuted and fined up to $222 a day and receive a criminal conviction. Generally, only a small number of people fail to complete the Census and go through the refusal process.

Also under the Act, if someone knowingly gives the ABS false or misleading information, they can be fined an amount of 10 penalty units ($2,220).

From the 2021 Census, 16 matters have been referred to the Commonwealth Director of Public Prosecutions (CDPP) for consideration due to persons failing to comply with a Notice of Direction.

Referrals to the CDPP are considered only after all reasonable attempts to achieve compliance using a cooperative approach have failed. The CDPP then decides if further action is taken against individuals who refuse to complete their Census form.   

The ABS is given the authority to collect, hold and use personal information for Census and statistical purposes as legislated by the Australian Bureau of Statistics Act 1975 and the Census and Statistics Act 1905.

The Census is the largest statistical collection undertaken by the ABS. The Census needed to reach everyone in Australia—regardless of where they are located, or their living circumstances, across the continent.

Across Australia, the scale of Census operations extended from the physical dimension—large distances, diverse climate, different terrain, to the people dimension—trust, cultural diversity, a common understanding of the purpose and value of the Census, and the other important factors like verifying the quality of the data captured, and looking after our Census staff.  

In capturing a comprehensive and inclusive picture of Australians and Australian communities, over ten million households were contacted by the ABS either by mail or by Field Officers.

Given the geography, distance, diversity of climate across such a vast country; six years of intensive planning and preparation was required.

Implementation of Census operations involved 35,000 temporary employees operating across every corner of Australia. We had Field Officers working across the country to help people complete their Census, including reminding them that their Census was due.

It is estimated that field staff completed a combined total of two million hours of work and travelled approximately 13 million kilometres in 2021, much of this  on foot going from door-to-door.

Fifty per cent of Australia’s land mass was covered by the Census remote team of 1,850 staff. For those living in remote Indigenous communities, the Census was conducted over an extended period between July and August. This ensured Census remote teams could cover vast areas and visit multiple communities.

Census information hubs were available in different part of the country for the public to seek information about the Census or access a paper form.  

Delivering a successful Census required planning for the diversity of people in Australia, including people with disability, people experiencing homelessness, Aboriginal and Torres Strait Islander, and culturally and linguistically diverse (CALD) communities. 

Special processes were put in place to count groups, such as people living in remote communities, and those in hospitals and hotels.

We provided support options for people who are deaf or hard of hearing, or blind or with low vision, including resources in Auslan and the ability to order Braille and large print forms.

Census information was translated to help Indigenous and multicultural communities to complete the Census. Information for people from a multicultural background was available in up to 29 languages and people had access to the Telephone Interpreter Service.

This was achieved through invaluable support from community organisations who helped us identify the needs of diverse communities and assisted us in planning our approach and sourcing engagement staff that could raise awareness about the Census to their members.    

For the 2021 Census, we had the added dimension of responding to the evolving COVID-19 situation.

We undertook extensive planning in the event of a COVID-19 outbreak. The safety of the community and our staff was and is our number one priority. We watched the COVID-19 environment closely to make sure our safety measures were up-to-date and met the guidelines and advice from government. Looking beyond the collection phase, data from the 2021 Census will be released in three phases—June and October 2022, and March 2023.

The Census is the largest statistical collection undertaken by the ABS, and one of the most important. Counting each person and dwelling on Census night takes a lot of planning, and many people.

The bulk of Census staff are employed to deliver Census materials to homes, or to visit homes after Census night where we haven’t received a completed form.

Specialist field staff are also recruited to support people who are hard to reach or who may need help completing their Census.

For the 2021 Census, we recruited approximately 32,000 field staff. This included teams working in remote communities, ensuring people sleeping rough were counted and providing language assistance.

The ABS advertised for its first temporary field staff positions in October 2020 and continued this recruitment up to and during the Census in August 2021.

Recruitment of the Census temporary workforce provided significant challenges:

• attrition was a considerable issue. Around 20 per cent of hires separated from the ABS before completing their employment contracts. 
• despite indicating willingness to travel on the application form, many applicants were not willing to travel for work outside of their immediate local area. This provided challenges to completing workloads in some areas.
• there were recruitment shortfalls for Census Field Officers in several regional/rural areas that relied on staff to drop off Census materials to households.
• COVID-19 impacted on the ability and willingness to work in roles that involved interacting with members of the public, despite safety measures in place.
• there was a competitive environment for recruitment due to lack of international travellers.

To address challenges, the ABS:

• commenced delivery of forms earlier than planned
• engaged with local community representatives
• set up travel teams
• mailed paper forms to households where possible
• mailed instructions to a large number of rural and remote areas
• set up community pop-up hubs for people to get access to paper forms.

In addition, for the first time, people were able to complete the Census online without receiving instructions in the mail. We referred to this as the no-login pathway and many households took up this option.

The first population counts in Australia were made as early as 1788.

From 1795 to 1825, ‘musters’ were held regularly where all members of the community gathered at specified locations to be counted.

In 1828, the first colonial Census was conducted in New South Wales, with Tasmania in 1841, South Australia in 1844, Western Australia in 1848, and Victoria in 1854.

In 1881, the first simultaneous Censuses of all the Australian colonies was conducted.

First ABS Census

In 1911, the first national Census was conducted by the Australian Bureau of Statistics (ABS). Around 7,300 people were appointed for the collection work.

Field Officers travelled by horse, cart and bicycle to collect forms across the country and the information gathered was tabulated by hand.

The Census was repeated in 1921, 1933, 1947, 1954, 1961, 1966 and from then on, every five years.

Evolution of the Census

In 1921, Census information was tabulated using mechanical machine equipment. 

The machines used in 1961 were so large that when delivered they could not fit through the door of the Census office in Canberra. A large hole had to be cut in the side of the wooden building to install them. The 1961 Census was the last to use tabulating machines.

In 1954, women were hired to process and code data for the first time. The 1967 Referendum mandated all Aboriginal and Torres Strait Islander peoples be counted in the Australian Census.  

Computer technology was first used to process Census information in 1966 and people were provided with the option to complete their Census online in 2006.

The 2021 Census was undertaken during a unique time in our history, when many areas across Australia were operating under lockdown restrictions due to COVID-19. Movements in and out of Australia were also restricted, limiting overseas travel for Australians and the number of overseas visitors within Australia.

The COVID-19 pandemic, and the subsequent restrictions, had many impacts on people’s daily lives, including employment, travel and education.

Depending on the area, restrictions included:

• limits on intra-state and interstate movement
• changes to private and public gatherings
• work from home orders
• stay at home orders
• remote learning requirements for students
• industries and businesses operating with staffing and/or density limits. 

Protecting the community and Census field staff

The ABS had planned for and was prepared to conduct the Census during the pandemic. Contingency plans were tested in a Census Test in October 2020. This included a COVID-safe plan, which detailed how we would deliver the Census, manage staff in the field and keep the community safe in line with government health orders. The ABS liaised with federal, state and territory governments regarding Census operations during COVID and regularly adapted to the changing circumstances to ensure safety measures were current.

The health and safety of Census staff and members of the community throughout Census operations was the highest priority. This was most important given the 2021 Census employed over 32,000 field staff.

Supporting everyone to complete the Census

Households across Australia were able to participate easily in the Census by completing it online or mailing back a paper form. The majority of people filled in their Census online, using instructions they received in the mail with no in-person contact from us.

For the first time, people were able to complete the Census online without receiving instructions in the mail. We referred to this as the no-login pathway and many households took up this option.

People living with COVID-19 lockdown restrictions were still required to complete the Census. Advice was provided on the website about how to respond to questions related to study and work if people’s circumstances were impacted.

The ABS supported people from culturally and linguistically diverse (CALD) communities, and Aboriginal and Torres Strait Islander people. Web content and social media was delivered in 25 CALD languages, and we trained 21 Indigenous spokespeople and 15 CALD spokespeople to support media engagement. 27 in-language fill-in-form sessions and information videos were uploaded to the Census website and ABS YouTube channel in response to COVID-19 restrictions.

We recruited locally from within community to engage with Aboriginal and Torres Strait Islander people. Census materials and resources for these audiences used culturally appealing artwork and Census advertising was translated into 19 Aboriginal and Torres Strait Islander languages.

Many people commented on how easy it was to complete the Census and receive help if they needed it.

What will the Census tell us about the pandemic?

This Census will be the first major data insight showing the impacts of COVID-19 on the living and working arrangements of everyone in Australia.

COVID-19 data insights are as important as those from previous Australian Censuses delivered during and immediately following significant world events. Past Censuses have helped us understand the effects of the Spanish Flu, the Great Depression, and World Wars on the economic and social make-up of Australia.

The 2021 Census will be no different, and the data we progressively release will have immediate and long-term value, revealing how the pandemic has changed life in Australia.

COVID-19 data insights will be available as part of the first release of Census data on 28 June 2022 and the second data release on 12 October 2022.

The Australian population has been living with the COVID-19 pandemic since January 2020. Since this time, Australians have dealt with lockdowns, closure of international borders, travel restrictions and periods of working and learning from home.

The 2021 Census was conducted on Tuesday 10 August 2021. People were required to complete the Census, even if they were in lockdown or quarantine. This Census represents a snapshot of Australia during the COVID-19 pandemic. Australia has been living alongside the pandemic for a long period, so it’s likely that many insights and trends identified at this time will continue.

Census data provides insights into how COVID-19 has changed life in Australia.

Census data quality statement

The ABS was prepared to conduct the Census during COVID-19. Procedures were set up well in advance of Census night, and when circumstances changed, the ABS adapted plans to respond quickly.

The official dwelling response rate was 96.1 per cent, up from 95.1 per cent in 2016.

The Australian Statistician established the Statistical Independent Assurance Panel, the Panel, to provide independent assurance and transparency of 2021 Census data quality.

The Panel has concluded that the 2021 Census data is fit for purpose, is of comparable quality to the 2011 and 2016 Censuses and can be used with confidence. The full report is now available.

COVID-19 restrictions on geographic areas

During the collection period for the Census, much of the eastern seaboard was under lockdown and travel was significantly restricted between and within states.

In areas under restrictions, Census face-to-face support activities like pop-up hubs and fill-in-form sessions were offered virtually, where possible. This was in line with the ABS Census COVID safe plan. These changes may have impacted how people accessed Census support.

On Census night, restrictions included:

• Australia’s international borders were closed.
• metropolitan Melbourne was under lockdown restrictions.
• regional Victorians could travel freely within regional Victoria. Travel to Melbourne could only occur under permitted reasons. Private gatherings in the home were not permitted.
• Cairns was under lockdown restrictions.
• NSW had lockdowns in the LGAs of Greater Sydney, Blue Mountains, Central Coast, Wollongong, Shellharbour, Tamworth, Ballina Shire, Byron Shire, City of Lismore and Richmond Valley Council.

Many areas experienced restrictions leading up to, on and after Census night. Some restrictions and areas changed on a day-by-day basis and in some cases, restrictions were implemented with a few hours’ notice. 

Comparing trends at a state/territory level may show variations in data due to the different restrictions in place across Australia, for example, Western Australia didn’t experience the same restrictions as NSW or metropolitan Melbourne.

See further information on Regional population.

International border restrictions

From 9pm AEDT Friday, 20 March 2020, Australia closed its borders to all non-citizens and non-residents. Almost two years later, the borders reopened on 21 February 2022.

Data for culturally and linguistically diverse (CALD) communities may have been impacted by border closures, for example, in agricultural areas that rely on a seasonal or transient migrant workforce on short term visas.

The 2021 Census counted fewer overseas visitors than previous Censuses with 61,860 overseas visitors counted on Census night. There were 315,531 overseas visitors counted on Census night in 2016.

The ABS has a range of data collections that can provide additional insights:

• Overseas Arrivals and Departures, Australia, March 2022 | Australian Bureau of Statistics (abs.gov.au)
• Overseas Migration, 2020-21 financial year | Australian Bureau of Statistics (abs.gov.au)

Seasonal populations

Many regions around Australia experience differences between their resident population and the ‘seasonal’ population. A seasonal population refers to people who temporarily access the services of an area. Regions experiencing these differences include:

• agricultural areas with a seasonal or transient migrant workforce on short term visas
• mining towns with fly in fly out workers
• tourist areas such as coastal towns that experience higher demand during the warmer months.   

Mostly, seasonal populations rely on being able to travel freely. For the southern states of Australia, many people visit sunbelt zones during winter months. For people in metropolitan Melbourne, restrictions may have impacted travel plans. Also, people from areas with no restrictions may have been reluctant to travel due to the risk of snap-lockdowns and not being able to travel back home.

Further resources

• Household Impacts of COVID-19 Survey, April 2022 | Australian Bureau of Statistics (abs.gov.au)
• Methods changes during the COVID-19 period | Australian Bureau of Statistics (abs.gov.au)

The 2021 Census collected information on where employed people aged 15 years or over worked in their main job in the week prior to the Census. The Census also collected information on where people worked and how they travelled to work.

The 2021 Census was conducted at a unique time during the COVID-19 pandemic. Across the country, there were areas in varying stages of restrictions on and around Census night (10 August 2021), resulting in many people working from home. This is likely to have impacted responses on Place of work and Method of travel to work.

The Census website and the online form included instructions for people to list their employer’s usual workplace address if they were working from home but had a workplace that they would otherwise attend.

Place of work and Method of travel to work datasets may look different in 2021 when compared to previous censuses due to the impact of COVID-19 on people’s working patterns.

Further resources

• Census dictionary – Place of work
• Census dictionary – Method of travel to work
• Information paper - Understanding Place of work data

Many areas experienced restrictions leading up to, on and after Census night. This resulted in more people working and studying from home and an increase in people being temporarily stood down during the Census collection period.

During August and September 2021, the Census website provided the following guidance on how to respond if subject to COVID-19 restrictions:

Income

Please reflect your usual income, as it was before the commencement of the current COVID-19 lockdown period or requirement to self-isolate.

Study and schooling

If you or your child are currently learning from home due to COVID-19 restrictions, please answer the questions reflecting the school or other educational institution you or your child would normally attend.

Workplace and job role

If you are currently working from home due to COVID-19 restrictions, but usually attend a workplace, please write the employer's usual workplace address.

If you were employed in the four weeks prior to the current lockdown period, but haven't been able to work in the last week due to lockdown or requirement to self-isolate, please:

• select 'Yes, but absent on holidays, on paid leave, on strike or temporarily stood down'.
• answer all questions reflecting your usual occupation. This includes your role (such as occupation and tasks performed) and information about your employer (such as industry and number of employees).

Answer all other questions about your commute and hours of work based on your current situation under COVID-19 restrictions.

Those who were not working four weeks prior to the lockdown were asked to select 'No, did not have a job'.

The 2021 Census form did not collect information on whether a person received an Australian Government COVID-19 payment.

Keeping people’s information safe, secure, and protected from cyber-attacks is of the utmost importance for the ABS.

Security and privacy were key factors in designing all elements of the 2021 Census particularly the Census Digital Service.

For 2021, the ABS completely rebuilt the Census Digital Service incorporating a range of security elements.

The ABS implemented state of the art cyber-security protections informed by the Australian Cyber Security Centre and other experts.

We also:

• undertook rigorous testing including, ethical hacks of our IT systems to ensure that our systems are robust
• ran a 24x7 Security Operations Centre to monitor Census systems with real-time information and alerts on potential security issues, and
• conducted independent security risk assessments of our Census systems by endorsed third party assessors through the Cyber Security Centre (ACSC) Information Security Registered Assessors Program (IRAP).

Ahead of the 2021 Census, the Digital Transformation Agency confirmed the Census Digital Service was compliant with the Digital Service Standards for Australian Government services.

All information collected in the Census is securely hosted in Australia and encrypted end-to-end. Only selected ABS staff could access the data.

In 2016, the online form experienced a significant outage on Census night. The ABS still received a 95 per cent response rate and delivered quality statistics as we had planned. The 2016 Census counted almost 10 million dwellings and 23.4 million people across Australia.

What happened on Census night?

The online Census form was targeted by a series of distributed denial of service (DDoS) attacks. Compounding the problem, an attempt to restore the system during the fourth DDoS attack led to the failure of one of our supplier’s routers.

Australians accessing the online form did not cause the problem, in fact 2.2 million households completed their forms prior to the outage; evidence that the system was not overloaded.

The Australian Signals Directorate reported the incident was a DDoS attack and that there was no unauthorised access to, or extraction of, any personal information. The online form was open to the Australian public, one day 18 hours and 44 minutes after the decision was taken to close the online form.

Why did the ABS close the online form?

Because, at the time, it was not known if the unusual outbound traffic from our systems was malicious or benign, we decided to close the online form to protect the privacy of the Australian public.

In a statement on 11 August 2016, the Australian Privacy Commissioner (and Acting Australian Information Commissioner) said they were satisfied that personal information was not inappropriately accessed, lost or mishandled.

2016 Census data

An Independent Assurance Panel reviewed the 2016 Census to provide assurance and transparency of its data quality. It considered issues including Census design, enumeration, processing and quality assurance, and using the quality of outputs from the 2011 and 2006 Censuses as benchmarks. 

A full copy of the report is available online. The Panel concluded that the 2016 Census data could be used with confidence. The 2016 Census data is of comparable quality to the 2011 and 2006 Census data. You can access the 2016 Census data from the ABS website

What was different in 2021?

We built a completely new online system, which enacted the findings of key 2016 reviews. The 2021 Census systems have been subject to independent review and we worked closely with key government security agencies to do everything possible to ensure the online form was safe, secure and easy to complete for the Australian community.

The occupancy for the majority of dwellings in Australia is determined by the returned Census form:

• a form with one or more people present on Census night is set to 'occupied'
• a form with all usual residents away on Census night is set to 'unoccupied'.

Dwellings from which no form is received have their occupancy determined by using a number of sources of information, including:

• ‘not at home’ forms submitted by residents through ABS online services
• residents who contacted the ABS with information
• intelligence from Census field staff making follow up visits to dwellings after Census night
• other requests and point of contacts with dwellings.

See further information on determining occupancy. 

Private dwellings marked as ‘unoccupied’ does not necessarily mean that the dwelling is long term vacant, rather it was vacant on Census night. 

Further resources

• Guide to Census data
• Census dictionary

The Census in Australia counts people where they are staying on Census night. This is known as ‘place of enumeration’. The Census form also asks questions about where the person usually lives, known as the ‘place of usual residence’. Information is collected on both locations to understand the resident population of an area and how it’s affected by seasonal populations on Census night. A seasonal population refers to people who temporarily access the services of an area.

The estimated resident population (ERP) is the official estimate of the Australian population. In line with international standards, the ERP is based on place of usual residence. ‘Place of usual residence’ refers to the address where a person has lived or intends to live for 6 months or more.
The ERP is used to plan for local government services and is used as the basis of some government funding distribution.

Being based on usual residence, the ERP is less likely to be influenced by seasonal populations. Many regions around Australia experience differences between their resident and seasonal populations, including:

• agricultural areas with a seasonal or transient migrant workforce on short term visas
• mining towns with fly in fly out workers
• tourist areas such as coastal towns that experience higher demand during the warmer months. 

Due to COVID-19 lockdown restrictions, areas that commonly experience seasonal populations may have been impacted by limits on international, intrastate and interstate movement. This is particularly clear in the data across the eastern seaboard states. For instance, there were drops in the number of people staying in the ski fields in Victoria and NSW on Census night. Other high tourist areas like the local government areas of Gold Coast, Cairns and Byron also show a drop in visitors. On the other hand, the data shows an increase in intrastate visitors in regional WA.

Internal migration data insights will be available as part of the second data release in October 2022.

The Census compiles information on same-sex couples based on responses to the relationship and sex questions on the Census form. Counts of same-sex couples living together have been compiled since the 1996 Census.

Census data provides a count of how many same-sex couples live together, and the characteristics of this population such as their age, marital status, and cultural background. However, there are some limitations associated with data from the Census that need to be considered.

The Census only measures relationships in each household, which means it does not count those relationships that extend beyond the household. Therefore, couples who were not living together are not included in couple/family variables.

Counts of couples are obtained using responses to the relationship questions on the Census form, so the way people responded to these questions determines if they were recorded as a couple or not. Respondents’ willingness to report their relationship status within the household can influence the data, and its possible this results in under reporting of relationships.

The Census does not capture information on gender, variations of sex characteristics, or sexual orientation. 2021 Census data is limited to people of the same sex who report being in a couple relationship and cannot be used as a count for diverse sexualities or be seen to be representative of lesbian, gay or bisexual populations overall.

In 2023, the ABS will be leading a public consultation process on the information to be collected in the 2026 Census.

Same-sex marriage

On 9 December 2017, the Marriage Act 1961 was amended to allow any two people the right to marry.

The 2021 Census was the first Census conducted since the marriage law was amended and therefore, registered same-sex marriages are reported for the first time.

Further reading

• Same-sex couples article
• Census dictionary
• The General Social Survey and National Study of Mental Health and Wellbeing collect information on gender.
• Standard for Sex, Gender, Variations of Sex Characteristics and Sexual Orientation Variables

The Census aims to accurately count the number of people in Australia on Census night. Since 1966, the ABS has run a Post Enumeration Survey (PES) shortly after the Census to independently assess the completeness of the Census count. The PES results are used to determine how many people should have been counted in the Census, how many people were missed and how many were counted more than once or in error.

People may be missed in the Census for several reasons. For example, a person may have mistakenly thought they did not need to complete the Census. People may also be counted on more than one Census form, such as children in shared care arrangements where the child is included on the Census forms of both households.

The ABS collects the PES through a short interview over the phone or in-person. The survey asks basic demographic details as well as location on Census night. This information is used to determine if, and where, a person should have been counted in the Census. It also supports the matching of PES person records to Census records to establish the number of times they were actually counted.

The difference between the PES estimate of how many people should have been counted in the Census and the actual Census count (including imputed persons) is known as the ‘net undercount’. Historically more people are missed than over-counted, resulting in a positive net undercount.

The ABS uses PES estimates of net undercount along with Census counts and administrative data to derive the estimated resident population (ERP) for 30 June of the Census year. PES results are also used to help identify improvements for future Censuses.

One of the most important uses of the Census is the part it plays in Australia’s Estimated Resident Population (ERP). The ERP is the official measure of Australia’s population. It includes all people who usually live in Australia, regardless of nationality or citizenship; including usual residents who are overseas for less than 12 months, and overseas visitors who are in Australia for more than 12 months.

With every Census comes a recalculation of the ERP. This is done by adding the net undercount from the Post Enumeration Survey (PES) to the Census counts and using administrative sources to calculate the ERP (based on the latest Census) for 30 June. In between Censuses, the ERP is updated quarterly for national and state and territory geographies. These updates use administrative data for births, deaths and migration. The ERP is updated annually for smaller areas like suburbs and local government areas.

The ERP:

• informs many planning decisions by government including forecasting needs for housing, health care, transport infrastructure, shopping centres, and child and aged care services
• is a major factor that determines electoral boundaries
• determines the number of seats in the House of Representatives
• guides the distribution of government funds to states and territories, which extends to local governments
• is the basis of population projections into the future.

Administrative data refers to information collected from administrative records rather than by direct contact with respondents. Using administrative data enhances how we run the Census and the quality of the information we collect. Administrative data was used in 2021 Census to:

• identify areas where people might need extra support to complete the Census, for example, employing field staff who speak the languages common in a particular area and who have similar cultural backgrounds.
• improve our estimate of the number of unoccupied houses on Census night for example, electricity connections and usage, rentals data and updates to address information for tax payments, can indicate which dwellings are more likely to be unoccupied.
• improve the accuracy of population counts by helping to estimate the number, age and sex of people in non-responding dwellings such as; combined data from the Australian Tax Office, Centrelink and Medicare records provides an indication of basic demographic household counts to inform this estimate.
• update our register of addresses by identifying new housing estates and demolition of residential dwellings.
• count people in hard-to-reach places including prisons and the Australian Antarctic base.
• help us support people staying in homelessness accommodation to participate in Census. Administrative data was also used to help accurately process Census data for these establishments such as supported and temporary accommodation.

Administrative data has strong potential but it cannot be used to replace the Census entirely. Most of the information collected on the Census is not currently available from administrative data sources. This may change, but for now, administrative data is best used to assist and complement the Census.

All Census data, including administrative data, is collected under the Census and Statistics Act 1905 and the Privacy Act 1988. This means ABS can only use it for statistical purposes, data is kept secure and confidential, and data is not shared or released in a way that could identify anyone.

Role and responsibilities

The Australian Statistician established the Statistical Independent Assurance Panel, the Panel, for the 2021 Census to provide independent assurance and transparency of 2021 Census data quality.

The Panel is tasked with reviewing the 2021 Census data by considering Census design, data collection, processing and that quality assurance measures are in place. Quality assurance measures and results from the Post Enumeration Survey are also analysed.

The Panel compares 2021 Census data to the data quality of recent Australian Censuses as benchmarks to ensure its fit-for-purpose and can be used with confidence. Comparisons will also be made to secondary data sources where available.

The Panel report will be published at the same time as the first data release in June 2022.

The ABS supports information requests from the Panel (provided they are consistent with relevant legislation, such as the Census and Statistics Act 1905).

Committee membership

The Panel is made up of experts with diverse experience. Members include:

• Chair – Professor Sandra Harding AO, Emeritus Professor, James Cook University
• Leanne Liddle, Director, Aboriginal Justice Unit, Department of Attorney-General and Justice, Northern Territory Government
• Professor Peter McDonald AM, Emeritus Professor, Head of Demography, Centre for Health Policy, University of Melbourne
• Peter Morrison, former Assistant Chief Statistician of Canada
• Dennis Trewin AO, former Australian Statistician (2000-2007)
• Stephen Walters, Chief Economist, New South Wales Treasury and member of the Australian Statistical Advisory Council.

The Panel will provide an independent view of the quality of selected variables and broad-based analysis of the 2021 Census of Population and Housing.