2970.0.55.010 - 2001 Census of Population and Housing - Fact Sheet: Population Measures, 2001  
ARCHIVED ISSUE Released at 11:30 AM (CANBERRA TIME) 03/06/2002  First Issue
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Population Measures

Australia's population can be measured in several ways:

  • Census counts by place of enumeration;
  • Census counts by place of usual residence; and
  • estimated resident population.

In addition, the Census also provides counts of:

  • the working population; and
  • families and households

Census Counts - Place of Enumeration

The census count for place of enumeration is a count of every person in Australia on Census Night, based on where they were located on that night. This may or may not be the place at which they usually reside.

It includes:
  • people on board vessels in or between Australian ports, or on long-distance trains, buses or aircraft;
  • people entering Australia from overseas before midnight on Census Night; and
  • Australian residents in Antarctica.

It excludes:
  • people leaving an Australian port for an overseas destination before midnight on Census Night;
  • Australian residents out of the country on Census Night; and
  • overseas diplomatic personnel and their families in Australia.

Visitors to Australia are counted regardless of how long they have been in the country or how long they plan to stay. In the 1996 Census, Overseas visitors were those people who indicated they would be usually resident in Australia for less than six months. For the 2001 Census, this has been changed to less than one year. Data on Overseas visitors is only available for three variables; Age (AGEP), Sex (SEXP) and Marital Status (MSTP). A special 'Overseas visitor' category has been created for all other person variables.

Census count by place of enumeration provides a snapshot in any given area. Although the Census is timed to attempt to capture the typical situation, the large number of visitors to holiday resort areas, such as the Gold Coast and snow fields, may result in a high enumeration count compared with the usual residence count.

Most standard output products from the Census provide characteristics of people on a place of enumeration basis. Counts can be provided for individual Collection Districts (CDs), and aggregations of CDs, such as postal areas or Statistical Local Areas (SLAs).

Census Counts - Place of Usual Residence

The census count for place of usual residence is a count of every person in Australia on Census Night, based on the area in which they usually live. Each person is required to state his/her address of usual residence on the census form. Where sufficient information is provided, this enables the area in which they usually reside to be identified and coded.

Census counts compiled on this basis are less likely to be influenced by seasonal factors such as the snow season, and provide information about the usual residents of an area.

The 2001 Census is the first census where usual residence data for Census Night will be available at CD level. Previously, place of usual residence was only coded to SLA level. Where the respondent has given insufficient address information, their SLA will be imputed as in the past. Their CD however, will not be imputed in these cases, but instead will be classified as 'Inadequately described'.

Estimated Resident Population

The Estimated Resident Population (ERP) is the official ABS estimate of the Australian population. Amongst its many uses, it is used to determine the number of representatives from each State (and Territory) to sit in the House of Representatives. It is also used to help determine the annual allocation of Commonwealth funds for State governments and for local government. The ERP is based on Census of Population and Housing usual residence counts. It is compiled as at 30 June of each census year and updated quarterly between censuses. These intercensal estimates of the resident population are revised each time a population census is conducted.

The ERP is based on census usual residence counts, and taking account of the following three important factors:
  • Census net underenumeration (or undercount). The level of underenumeration is derived from the Post Enumeration Survey which is conducted soon after the Census, and from estimates based on demographic analysis.
  • Australian residents who are temporarily overseas on Census Night and are therefore not covered by the Australian Census. The number of such people is obtained from statistics on overseas arrivals and departures.
  • The Census does not fall on 30 June. For example, the 2001 Census was held on 7 August. Back dating of population estimates from 7 August to 30 June is accomplished using data from birth and death registrations, overseas arrivals and departures, and estimates of interstate migration, for the period 1 July to 7 August.

The Working Population

The working population consists of all persons who were employed in the week prior to Census Night. It is not possible to distinguish between workers working standard hours, and shift workers, as the data collected relate to all workers.

The working population can be used to calculate daytime populations which are particularly relevant in commercial and industrial areas. Many services need to be located where people will be during the day, rather than where they live. These data, when combined with statistics on how people get to work and on the availability of cars, are used to plan for roads and public transport.

Families and Households

Family and household data from the Census are based on persons usually resident. When coding the variables Family Type (FMTF) and Household Type (HHTD) , information about usual residents temporarily absent is taken into account and visitors to the household are disregarded.

Age, sex, student status and relationship information are collected for persons temporarily absent, as this is sufficient for family and household coding purposes. Detailed characteristics of these 'temporary absentees' are not included on the family or household record.

Coders may use the following temporary absentees in determining household and family classifications:
  • partners,
  • children; and
  • co-tenants or unrelated flatmates (used to classify group households).

Note that family and household structures are not coded for dwellings where all occupants are absent on Census Night, for example, on holidays. The dwelling would be classified as unoccupied and the holidaying family would be coded as a visitor only household at the holiday home.