AUSTRALIAN BUREAU OF STATISTICS, ESTIMATED RESIDENT POPULATION

INTRODUCTION

1 The Estimated Resident Population (ERP) is the official estimate of the Australian population.

2 It is a requirement of the Census and Statistics Act 1905 for the Australian Bureau of Statistics (ABS) to compile quarterly population estimates for each Australian state and territory. There are further Acts of Parliament which require population estimates including:

• Commonwealth Electoral Act 1918
• State Grants (General Purposes) Act 1994
• Local Government (Financial Assistance) Act 1995
• A New Tax System (Commonwealth-State Financial Arrangements) Act 1999.

3 In this product estimates of the resident population are presented by age and sex. Data are also presented on population density and annual population change.

SCOPE

4 The scope of ERP is based on census counts of all usual residents (except diplomatic personnel and their families). The scope also includes the number of Australian residents estimated to have been temporarily overseas at the time of the Census of Population and Housing.

5 Excluded from scope are overseas visitors in Australia for less than 12 months.

REFERENCE PERIOD

6 The ERP is calculated for different reference periods for different populations and geographical areas. The ERP for Australian states and territories is calculated quarterly as at 31 March, 30 June, 30 September and 31 December each year. Local Government Area (LGA) estimates are available annually for 30 June. In this product data are presented as at 30 June 2006.

7 ERP is produced in three different stages to meet the conflicting demands of accuracy and timeliness. These are referred to as preliminary, revised and final estimates. In general, preliminary estimates at national and state/territory levels are available six months after the reference period (and nine months for sub-state/territory estimates). Revised estimates are available 21 months later, once revisions to net overseas migration have been taken into account, and final estimates area available after the following census.

8 In this product the estimates presented for 2002 through 2006 are preliminary rebased estimates based on 2006 Census usual residence data and 2006 geography. The estimate for 2001 is a finalised estimate based on the 2001 Census.

KEY DATA ITEMS

9 The following definitions are used in this product:

10 Average annual rate of growth: The average annual rate of population growth, r, is calculated as a percentage using the formula below, where Po is the population at the start of the period, Pn is the population at the end of the period and n is the length of the period between Pn and Po in years.

11 Estimated Resident Population: The official measure of the population of Australia is based on the concept of residence. It refers to all people, regardless of nationality or citizenship, 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. It excludes overseas visitors who are in Australia for less than 12 months.



12 Population density: The number of people per square kilometre.

13 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.

GEOGRAPHY

14 Estimates of the resident population are coded according to the Australian Standard Geographical Classification (ASGC) (cat. no. 1216.0). In this product data has been coded according to the 2006 edition.

15 ERP is published for Statistical Local Areas (SLAs), Local Government Areas (LGAs), Statistical Subdivisions (SSDs), Statistical Divisions (SDs), Statistical Districts, States and Territories, and Australia. In this product, ERP data are presented for each LGA in NSW.

METHOD OF ESTIMATION

16 Estimates of the resident population are based on Census counts by place of usual residence (excluding overseas visitors in Australia), with an allowance for net Census undercount, to which are added the number of Australian residents estimated to have been temporarily overseas at the time of the Census.

17 Population estimates are updated by adding to the estimated population at the beginning of each period, the components of natural increase (births minus deaths, on a usual residence basis) and net overseas migration. For the States and Territories, account is also taken of the estimated interstate movements involving change of usual residence.

LOCAL GOVERNMENT AREA ESTIMATES

18 Due to the absence of migration data at LGA level, ERP at this level is calculated using a mathematical model. The model establishes a relationship between changes in a population and changes in indicators, such as dwelling approvals and Medicare enrolments, between the two most recent Censuses. The choice of indicator varies across LGAs depending on aspects such as whether the area is urban or rural, and whether the area is growing or otherwise. Changes in these indicators are then used to estimate changes in the population of each area since the last Census. Local knowledge, including that advised by local governments, may be used to adjust the outcome for a particular LGA.

19 After each Census (at 30 June of the Census year), estimates for the preceding intercensal period are revised by incorporating an additional adjustment (intercensal discrepancy) to ensure that the total intercensal increase agrees with the difference between the estimated resident populations at the two 30 June dates in the respective Census years.

ACCURACY

20 Efforts are made to reduce inaccuracies in the calculation of ERP. After each Census, an evaluation is conducted into the accuracy of all components of population estimation and estimation models. A measure of accuracy is obtained by comparing the latest Census date estimates with the corresponding estimates which have been updated from the previous Census date.

21 After the 1981 Census of Population and Housing, an important change was made to the concept of what constitutes the population. Previously, population was defined as the number of people actually present at a given time (at the Census). This meant the number of people actually counted and therefore included foreign tourists but excluded Australians abroad. It was decided to define population as the number of residents, i.e. people who usually reside in Australia. Population estimates based on this new concept of population were constructed back to 1971.

METADATA

22 Further information about ERP is available in Demographic Estimates and Projections: Concepts, Sources and Methods (cat. no. 3228.0). Further information on Indigenous ERP is available in Experimental Estimates and Projections, Aboriginal and Torres Strait Islander Australians (cat. no. 3238.0) and Issues in Estimating the Indigenous Populations (ABS Demography Working Paper 2001/4) (cat. no. 3126.0). These publications can be found on the ABS web site.

PUBLISHED DATA

23 The main source of published ERP data is available in Australian Demographic Statistics (cat. no. 3101.0), Regional Population Growth, Australia (cat. no. 3218.0), and Population by Age and Sex, Australian States and Territories (cat. no. 3201.0).

24 The main source of published Indigenous ERP is Experimental Estimates and Projections, Aboriginal and Torres Strait Islander Australians (cat. no. 3238.0).

ABS DATA AVAILABLE ON REQUEST

25 As well as the statistics included in this and related publications, the ABS may have other relevant data available on request. For further information, please contact the National Information and Referral Service on 1300 135 070.