• Summary
• Downloads
• Explanatory Notes
• Related Information
• Past Releases

INTRODUCTION

1 For Australia, this publication contains estimates of the resident population of SLAs, LGAs, SSDs, SDs, Statistical Districts, states and territories, and Australia. For New Zealand, estimates of the resident population are provided for Regional Councils, Territorial Authorities and New Zealand.

2 To meet the conflicting demands for accuracy and timeliness there are three estimates of sub-state/territory populations. Preliminary estimates are normally available eight months after the reference date (i.e. February), revised estimates a year later and final estimates after the following census. The Australian estimates in this publication are final for 1999, based on results of the 2001 Census of Population and Housing. Estimates for 2003 have been revised, while estimates for 2004 are preliminary, based upon the final 2001 estimates.

ESTIMATED RESIDENT POPULATION - AUSTRALIA

3 Estimated resident population (ERP) are official estimates of the Australian population, which links people to a place of usual residence within Australia. Usual residence is that place where each person has lived or intends to live for six months or more from the reference date for data collection.

4 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.

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

6 After each census, estimates for the preceding intercensal period are revised by incorporating an additional adjustment (intercensal discrepancy) to ensure that the total intercensal change agrees with the difference between the ERPs at the two respective census dates.

Estimation of sub-state/territory populations

7 In census years the ERP as at 30 June for each SLA is calculated based on usual residence census counts, excluding overseas visitors in Australia, with an allowance for net census undercount and the number of residents temporarily overseas at the census date. As the census is held at a date other than 30 June (the 2001 census was held on 7 August), further adjustments taking into account births, deaths and migration for the intervening period are made to obtain the ERP at 30 June. The population estimates for LGAs and other regions are built up from the SLA estimates.

8 For post-censal years, the absence of migration data at the SLA level means that it is not possible to estimate SLA populations by taking into account natural increase and net migration. Instead, ERPs are calculated using a mathematical model. Local knowledge, including that advised by local governments, may be used to adjust the outcome of the model for a particular SLA.

9 In the mathematical model a relationship is established between changes in population and changes in other indicators between the two most recent censuses. The choice of indicators varies across the states and territories, depending on availability and indicative ability, and includes dwelling approvals, electricity connections, Medicare enrolments and drivers' licences. The choice of indicators also varies within states/territories, depending on aspects such as whether the SLA is urban or rural, is growing or declining, and has a high or low proportion of medium and high density dwellings. Changes in these indicators are then used to estimate changes in the population of each area since the last census.

Accuracy of sub-state/territory population estimates

10 In census years, both preliminary estimates (derived from updating the ERPs from the previous census) and final estimates (based on the current census) are prepared. Differences between these two sets of estimates are referred to as intercensal errors. An indication of the accuracy of ERPs can be gauged by assessing the size and direction of the intercensal errors. For Australia, the preliminary June 2001 ERP under-estimated the final June 2001 ERP by 0.1% (-26,600 persons). For the states/territories, the 2001 intercensal errors ranged from -1.6% (Australian Capital Territory) to +0.5% (Victoria).

11 Summary statistics of the absolute values of these errors can be used to assess a number of population estimates. The average absolute value of the intercensal errors for the 2001 series of SLA estimates (excluding regions with an ERP less than 500) was 3.8%, a decrease on the 1996 average of 4.6%. For LGAs, the 2001 average absolute intercensal error (excluding regions with an ERP less than 500) was 3.6%, an increase on the 1996 average of 3.4%.

12 Average absolute intercensal errors for the 2001 series of LGA estimates decreased with increasing population size; that is, LGAs with large populations recorded the smallest percentage errors while small LGAs recorded the largest percentage errors.

Average absolute intercensal error, Australia - 30 June 2001
	Number of LGAs	Average absolute intercensal error
Size of LGA (people)	no.	%
Under 500	21	10.5
500 to 1,999	93	7.7
2,000 to 4,999	109	4.4
5,000 to 9,999	91	3.8
10,000 to 19,999	94	2.7
20,000 to 49,999	100	2.0
50,000 and over	116	1.5

Interpretation of LGA rankings

14 In Tables 1 to 7 LGAs are ranked within states and territories according to both 'largest' and 'fastest' growth, identifying areas in Australia currently experiencing significant changes in population size. Largest growth is based on the absolute change in population between June 2003 and June 2004, while fastest growth is based on the rate of change in population (that is, the percentage change in population) for the same period. LGAs with populations of less than 2,000 people at June 2003 have been excluded from the fastest growth rankings.

15 Due to the inherent imprecision of small-area population estimates, rankings should be considered indicative of relative growth between LGAs within each state and territory, not definitive.

Estimating ERPs for Northern Territory Community Government Councils and Queensland Aboriginal and Island Councils

16 The Australian Standard Geographical Classification (ASGC), 2003 (cat. no. 1216.0) introduced 29 new LGAs and corresponding SLAs in Northern Territory. These geographic areas are based on Community Government Councils (CGCs) which are representative Indigenous bodies. Previously, the population of these areas were included within the former SLA (and LGA or unincorporated Northern Territory) boundaries defined in earlier versions of ASGC (see Appendices 2 and 5). Similarly in Queensland, new LGAs and corresponding SLAs were introduced in 2002 for Aboriginal Council (AC) and Island Council (IC) areas (see Appendices 1 and 4).

17 The 30 June 2001 ERPs for these areas are based on 2001 Census of Population and Housing usual residence census counts as at 7 August 2001, adjusted for net undercount (including demographic adjustments), residents temporarily overseas and backdated to 30 June based on estimates of natural increase and net migration. Population estimates for these areas which do not correspond to ASGC 2001-based SLAs are compiled by apportioning the 30 June 2001 ERP of the former SLA(s) to 2001 census based Collection Districts (CDs) within each SLA using 2001 census usual residence counts at the CD level. CDs, or aggregations of CDs which directly correspond to the SLAs are then used to aggregate apportioned CD level population estimates to derive an estimated population of each of the ASGC 2003-based SLAs. In some cases where SLA boundaries do not correspond directly to 2001 census CD boundaries, estimates are made as to the share of population to be allocated from the CD to each relevant SLA.

18 The SLA to CD level apportionment method for estimating census-year populations has some limitations. Estimates of net undercount are apportioned to SLAs based on age, sex, Indigenous status, state and territory, and (for the six states) capital city/balance of state. However, the SLA to CD level apportionment assumes that net undercount is distributed to component CDs in proportion to the census usual residence counts. It is quite possible that there may be local clustering and regional differences in net undercount which cannot be practically or efficiently measured. SLA level estimates of the number of residents temporarily overseas on census night are based on coding addresses of residence to SLA from a sample of incoming passenger cards. The apportionment process assumes these are distributed to CDs in proportion to the census usual counts. Data are not available retrospectively for the newly defined SLAs and LGAs for births and deaths between the 30 June and the census date. Similarly, no data are available on net migration for the new SLAs. Accordingly, the population estimates for new SLAs based on CD level apportionment are reasonable approximations in the absence of finer level components.

19 For the Queensland AC and IC areas, additional administrative and local knowledge was used to estimate for population change from 30 June 2001 to 30 June 2002 in the 2001-02 issue of this publication.

20 Unlike most SLAs and LGAs in Australia, the ABS has not been able to estimate population change for the new CGC LGAs and SLAs in the Northern Territory for June 2002 onwards, and the AC and IC LGAs and SLAs in Queensland for June 2003 onwards. At the present time the ABS has not been able to identify any data sources that can yield reliable and comprehensive information on annual population change for these small communities. For Queensland ACs and ICs a significant change occurred in a previously used data source limiting its suitability for estimating population change for these SLAs during 2002-03. Further, the small size and remoteness of some of these areas means that postcode address-based data sets are of limited use. The nature of postal delivery areas and the use of post box-based addresses which may not be a clear indication of place of residence also limits the utility of these data to estimate population change for these areas.

21 Where ABS has not been able to estimate annual population change, estimates in this publication have been represented as "np". In the accompanying electronic releases, the most recently published estimates (June 2002 for Queensland ACs and ICs, and June 2001 for NT CGCs) have been held constant to June 2004 to ensure individual estimates sum to totals. Although these estimates indicate no change in population over this period, it should not be assumed that this is the case.

22 Small populations are relatively more sensitive to small population changes which may not be detectable or quantifiable. However, larger populations contain much of this variability within the larger population.

23 For the time being, and in the absence of other reliable data sources, the ABS may only be able to produce population estimates for these SLAs and LGAs in census years using data from the five-yearly Census of Population and Housing. The ABS will continue to monitor the availability of other data sources for population change estimation in consultation with state, territory and local governments. For example, the inclusion of these areas in the ASGC will mean that in future, other data such as births and deaths by place of usual residence can be coded to these new geographic levels for future use in small area population estimation.

24 Population estimates for these SLAs and LGAs for periods between 1996 and 2001 have been prepared using interpolation techniques between 1996 and 2001 census year-based estimates.

25 A more detailed explanation of the concept of ERP, as adopted by the ABS for official population estimates, is contained in Demographic Estimates and Projections: Concepts, Sources and Methods, Statistical Concepts Library, ABS web site <www.abs.gov.au>.

SERVICE POPULATIONS

26 Service population estimates are a different measure of population. They take into account seasonal itinerant populations which are not included in the ERP. Currently the ABS does not produce service population estimates but two working papers are available which investigate the concept and feasibility of such estimates. The working papers are available on the ABS web site <www.abs.gov.au> by selecting Themes, then Demography, then ABS Demography Working Papers (numbers 96/4 and 99/3).

CORRECTION OF PRISON DATA OF QUEENSLAND

27 For the 2001 Census of Population and Housing, most prison data was received for processing via electronic data files. During the post-processing evaluation cycle, it has been established that the male and female counts for Queensland prisons (only) were incorrectly captured. This has resulted in the publication of incorrect sex census counts for males and females for various Queensland geographical areas and as a consequence, the Australian population totals. For population estimates, revisions to Queensland have been applied over the financial year 2001-02. Revised estimates for 30 June 2002 by age and sex and SLA/LGA are currently avaialble. Revision to population estimates for the 1996-2001 intercensal period are not planned. However, information on the SLAs and LGAs and other geographic areas affected are available in the 2001 Census Working Paper - Fact Sheet: Correction of Prison Data of Queensland on the ABS web site <www.abs.gov.au>.

ESTIMATED RESIDENT POPULATION - NEW ZEALAND

28 The estimated resident population of New Zealand, and any area of New Zealand, at 30 June in the year of the latest census is based on the latest census usually resident population counts updated for net census undercount, the number of residents temporarily overseas on census night, births, deaths and net migration between census night and 30 June, and reconciliation with demographic estimates at ages 0-9 years.

29 Subsequent national population estimates are produced by updating previous estimates using births, deaths and external migration data for the current quarter.

Subnational population estimates

30 Subnational population estimates are produced annually, as at 30 June. The estimation of subnational resident population uses the same component method as is used for estimates of the total national population, but with the addition of an extra component - internal migration between the subnational areas of New Zealand.

31 As no data on current internal migration is available, internal migration is estimated indirectly, using 'symptomatic' data, including building consents, occupancy rates, full-time equivalent employment, numbers of people in institutions (e.g. prisons), armed forces data, and past internal migration (from the most recent intercensal period). This information is supplemented by information from Territorial Authorities and universities. More details are available on request from Manager, Demography Division, Private Bag 4741, Christchurch, New Zealand.

AUSTRALIAN STATISTICAL AREAS

32 This publication contains data presented according to the Australian Standard Geographical Classification (ASGC) 2004 Edition, which refers to boundaries as defined at 1 July 2004. Under this classification, statistical areas are defined as follows:

• Local Government Areas (LGAs). These areas are the spatial units which represent the geographical areas of incorporated local government councils, an Aboriginal or Island Council in Queensland, or a Community Government Councils in the Northern Territory. The various types of LGAs are Aboriginal Councils (AC), Areas (A), Boroughs (B), Cities (C), Community Government Councils (CGCs), District Councils (DC), Island Councils (IC), Municipalities (M), Regional Councils (RegC), Rural Cities (RC), Shires (S), and Towns (T).
• Statistical Local Areas (SLAs). These geographical areas are, in most cases, identical with, or have been formed from a division of, whole LGAs. In other cases they represent unincorporated areas. In aggregate, SLAs cover the whole of a state or territory without gaps or overlaps. In some cases legal LGAs overlap Statistical Subdivision boundaries and therefore comprise two or three SLAs (Part A, Part B and, if necessary, Part C).
• Statistical Subdivisions (SSDs). These are of intermediate size, between SLAs and SDs. In aggregate, they cover the whole of Australia without gaps or overlaps. They are defined as socially and economically homogeneous regions characterised by identifiable links between the inhabitants. In the non-urban areas an SSD is characterised by identifiable links between the economic units within the region, under the unifying influence of one or more major towns or cities.
• Statistical Divisions (SDs). These consist of one or more SSDs. The divisions are designed to be relatively homogeneous regions characterised by identifiable social and economic units within the region, under the unifying influence of one or more major towns or cities.
• Statistical Districts. These consist of selected, significant, predominantly urban areas in Australia which are not located within a Capital City SD. Statistical Districts enable comparable statistics to be produced about these selected urban areas.

34 Further information concerning statistical areas is contained in Australian Standard Geographical Classification, 2004 (cat. no. 1216.0).

MAPS

35 A complete series of maps showing the SLAs mentioned in this publication is available in Australian Standard Geographical Classification, 2004 (cat. no. 1216.0).

36 The centre of population is one measure used to describe the spatial distribution of a population. The method of calculation used in this publication for the map on page 10 is based on the 'centroid' (i.e. centre) and population of each SLA in Australia. Latitude and longitude coordinates of the centroid of each SLA are multiplied by the SLA's estimated resident population to obtain weighted latitudes and longitudes. These are summed to obtain a weighted latitude and longitude coordinate for all Australia, then divided by the total population of Australia to obtain a single latitude and longitude coordinate, the centre of population.

37 Due to the inherent imprecision in small-area estimates, and the choice of SLA-level estimates in the above calculation (rather than estimates at a different geographical level, for example, the Census Collection District or Local Government Area level), the centre of population should be considered indicative only of the distribution of population, and cannot be ascribed to an exact location. Use of different geographical level data would result in a slightly different centre of population.

AVERAGE ANNUAL RATE OF GROWTH

38 The average annual growth rate is calculated as a percentage using the formula below, where P₀ is the population at the start of the period, P_n is the population at the end of the period and n is the length of the period between P_n and P₀ in years.

CALCULATION OF AREAS

39 The area figures quoted in this issue are based upon the SLA level of the Australian Standard Geographical Classification, 2004 (cat. no. 1216.0). The areas of the SLAs were calculated using ABS standard Geographic Information Systems software from the digital boundaries of the ASGC 2004. Higher level spatial unit area figures are subtotals of the SLA areas.

ELECTRONIC DATA

40 Annual population estimates at 30 June for all SLAs in Australia are available electronically. This information can be customised to provide data for any choice of years and any combination of states and territories. Electronic copies of this publication (in .pdf format), plus current and earlier year estimates for all SLAs in Australia, are available from the ABS web site <www.abs.gov.au>. These and other downloadable products are available for purchase online using a credit card. They can be downloaded (with no credit card needed) by AusStats and ABS@ subscribers, Australian universities and at some public libraries. If you are not an AusStats subscriber inquiries can be made to Information Services (see the back cover of this publication for contact details). Inquiries for New Zealand data should be directed to Statistics New Zealand (email <info@stats.govt.nz>).

ACKNOWLEDGMENT

41 ABS publications draw extensively on information provided freely by individuals, businesses, governments and other organisations. Their continued cooperation is very much appreciated; without it, the wide range of statistics published by the ABS would not be available. Information received by the ABS is treated in strict confidence as required by the Census and Statistics Act 1905.

RELATED RELEASES

42 Other ABS releases that may be of interest to users of this publication include:

Census of Population and Housing: Population Growth and Distribution, Australia, 2001, cat. no. 2035.0
Australian Demographic Statistics, cat. no. 3101.0
Australian Historical Population Statistics, cat. no. 3105.0.65.001, available on <www.abs.gov.au>. From the navigation bar select Statistics, then Companion Data; 31. Demography - general
Integrated Regional Data Base (IRDB), Australia, cat. no. 1353.0
Population by Age and Sex, Australian States and Territories, cat. no. 3201.0
Population by Age and Sex, cat. no. 3235.0-8.55.001 - state and territory-specific datasets, available on <www.abs.gov.au>. From the navigation bar select Statistics, then Data Cubes, then 32. Population trends and estimates.
Regional Statistics, cat. no. 1362.1-4,1362.6-8 - state and territory-specific publications
Australian Standard Geographical Classification (ASGC), 2004, cat. no. 1216.0

44 Current publications and other products released by the ABS are listed in the Catalogue of Publications and Products (cat. no. 1101.0). The Catalogue is available from any ABS office or the ABS web site <www.abs.gov.au>. The ABS also issues a daily Release Advice on the web site which details products to be released in the week ahead.

45 As well as the statistics included in this and related publications, additional information is available from the ABS web site <www.abs.gov.au> by selecting Themes then Demography.