3101.0 - Australian Demographic Statistics, Jun 2016 Quality Declaration 
Latest ISSUE Released at 11:30 AM (CANBERRA TIME) 15/12/2016   
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EXPLANATORY NOTES


INTRODUCTION

1 This quarterly release contains the most recent estimates of the resident populations (ERP) of Australia and the states and territories based on the results of the 2011 Census of Population and Housing held on 9 August 2011 (with various adjustments described in paragraphs 5 and 6), and the addition of quarterly components of population growth. The ABS has used the 2011 Census to produce final rebased estimates of the resident population for the series from September 1991 to June 2011. This release contains the latest available statistics on births, deaths (including infant deaths) and overseas and interstate migration. In addition, the release includes estimates of the resident population by age groups, major population regions and estimates and projections of the Aboriginal and Torres Strait Islander population. It also includes projected resident populations and projected number of households (2011 base). Periodically, articles on specific demographic topics will be released on the ABS web site in conjunction with this release.

2 Following the 1992 amendments to the Acts Interpretation Act to include the Indian Ocean Territories of Christmas Island and the Cocos (Keeling) Islands as part of geographic Australia, population estimates commencing from September quarter 1993 include estimates for these two territories. To reflect this change, another category of the state and territory level has been created, known as Other Territories. Other Territories include Jervis Bay Territory (previously included with the Australian Capital Territory), as well as Christmas Island and the Cocos (Keeling) Islands which were previously excluded from population estimates for Australia. Data for Other and External Territories are detailed separately in table 8.

3 From 1 July 2016 the Norfolk Island Legislation Amendment ACT 2015 and subsequent related Acts enable the Australian Government to resume responsibility for administering the External Territory of Norfolk Island following a period of self-government since 1979. With respect to population data, the Administration of Norfolk Island carried out its last census on 9 August 2011 and maintains a regular and reliable set of population statistics which is publicly available. The 2011 Census revealed a population of 2,302 people made up of 1,795 Norfolk Islanders and 507 visitors, where Norfolk Islanders were classified as 'those people who were present and living on Norfolk Island on 9 August 2011 and comprising Residents, General Entry Permits (GEP), Temporary Entry Permits (TEP) and secondment officers'. The population of Norfolk Island in this release makes use of Administration of Norfolk Island data.

4 Estimates for Australian External Territories will be updated annually as at 30 June unless a more recent estimate is required for electoral apportionment purposes under the Commonwealth Electoral Act 1918.


POPULATION AND COMPONENTS OF POPULATION CHANGE

5 Australia’s population estimates for the period since 1971 are compiled according to the place of usual residence of the population. An explanation of the place of usual residence conceptual basis for population estimates is given in Information Paper: Population Concepts, 2008 (cat. no. 3107.0.55.006) and also in Population Estimates: Concepts, Sources and Methods, 2009 (cat. no. 3228.0.55.001).


Method of estimation

6 The estimated resident population is an estimate of the Australian population obtained by adding to the estimated population at the beginning of each period the component of natural increase (on a usual residence basis) and the component of net overseas migration. For the states and territories, estimated interstate movements involving a change of usual residence are also taken into account. Estimates of the resident population are based on Census counts by place of usual residence, to which are added the estimated Census net undercount and the number of Australian residents estimated to have been temporarily overseas at the time of the Census. Overseas visitors in Australia are excluded in this calculation.

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


Status of quarterly ERP data

8 The status of quarterly ERP data changes over time from preliminary to revised to final as new component data becomes available. The table below shows the current status of ERP and the components of population change: natural increase, net overseas migration and net interstate migration.

Status of quarterly Estimated Resident Population (ERP) data, as at 15 December 2016

Census base Natural increase Net overseas migration Net interstate migration ERP STATUS

Sep.1991-Jun. 2006 Based to 1996, 2001 & 2006 Censuses as applicable Final (Recast) Final (Recast) Final (Recast) FINAL (RECAST)
Sep. 2006-Jun. 2011 2011 Census Final Final Final FINAL
Sep. 2011-Mar. 2015 2011 Census Revised - based on date of occurrence Revised - based on actual traveller behaviour Preliminary - based on modelled expansion factors from 2011 Census REVISED
Jun 2015 2011 Census Revised - based on date of occurrence Preliminary - based on modelled traveller behaviour one year ago Preliminary - based on modelled expansion factors from 2011 Census PRELIMINARY
Sep. 2015-Jun. 2016 2011 Census Preliminary - based on date of registration Preliminary - based on modelled traveller behaviour one year ago Preliminary - based on modelled expansion factors from 2011 Census PRELIMINARY

Note: 'Final (Recast)' refers to recast estimates based on 2011 ERP.



Natural increase: births and deaths

9 Natural increase is a major component of ABS quarterly state and territory population estimates and is calculated using the estimated number of births and deaths. The births and deaths data in this release are shown by state and territory of usual residence, using year/quarter of registration for preliminary data and year/quarter of occurrence for both revised and final data. This may affect time series comparisons within relevant tables. For preliminary estimates, births and deaths by quarter of registration are used as a proxy for quarter of occurrence. For revised estimates, a factor has been applied to the number of occurrences to allow for those occurrences which were yet to be registered at the time of revision. For final estimates between 30 June 1991 and 30 June 2011, year/quarter of occurrence data are used. For further details see Demography Working Paper 1998/2 - Quarterly Birth and Death Estimates, 1998 (cat. no. 3114.0).

10 The timeliness and accuracy of ABS quarterly population estimates depend in part on the timeliness and accuracy of estimates of births and deaths which are based on registrations. To be able to provide timely estimates, the ABS produces preliminary estimates using births and deaths by quarter of registration as a proxy for quarter of occurrence. The major difficulty in this area stems from the fact that while the vast majority of births and deaths are registered promptly, a small proportion of registrations are delayed for months or even years. Lags or accumulations in births and deaths registrations can be caused by:
  • late notification of a birth or death event to a state or territory registry;
  • delays arising from incomplete information supplied for a registration;
  • procedural changes affecting the processing cycles in any of the state and territory registries; or
  • resolution of issues that may arise within the ABS or registry processing systems.

11 Preliminary birth and death estimates are subject to fluctuations caused by lags or accumulations in the reporting of births and deaths registrations. Accumulations can result from the eventual processing of lagged registrations in a later quarter. As a result, preliminary quarterly estimates can be an underestimate or an overestimate of the true numbers of births and deaths occurring in a reference period.

12 Selected birth and death registration data contributing to preliminary estimates which are higher or lower than usual are noted below along with any explanations provided by the relevant state or territory registrars:
  • June 2016: Australia. The notable increase in birth registrations in this quarter is likely due to a processing catch up in birth registrations in several states. Revised data based on occurrence rather than registrations should lead to a more consistent series.
  • March 2016: Victoria. The higher than usual number of births registrations this quarter follows several quarters of lower than usual birth registrations. This increase is due to a processing catch-up following processing lags.
  • December 2015: Victoria. The notable increase in death registrations compared to previous December quarters is likely to be addressed with revisions based on occurrence data which should lead to a more consistent series. The increase may be a consequence of registration processing lags.
  • September 2015: Victoria. With the release of the June 2016 financial year death registrations the ABS has taken this opportunity to revise the September quarter 2015 death registrations for Victoria, in order to rectify the discrepancy previously found between the data files received by the ABS and the number of registrations processed by the registrar for that quarter (approximately 2,400 additional deaths).
  • September 2015: Victoria. The lower than usual birth registrations in the September quarter is due to processing delays. It is possible that this may lead to higher than usual registrations in the next quarter.


Net overseas migration

13 The United Nations defines an international migrant as "any person who changes his or her country of usual residence". For the purposes of estimating Net Overseas Migration (NOM), and thereby Australia's official ERP, a person is regarded as a usual resident if they have been (or expect to be) residing in Australia for a period of 12 months or more. This 12 month period does not have to be continuous and is measured over a 16-month period.

14 Conceptually NOM is the difference between incoming travellers who stay in Australia for 12 months or more over a 16-month period (NOM arrivals) and outgoing travellers who leave Australia for 12 months or more over a 16-month period (NOM departures).

15 The ABS introduced the '12/16 month' rule for calculating NOM in September quarter 2006. Consequently this point marks a break in series and NOM estimates from earlier periods are not comparable.

16 The Department of Immigration and Border Protection (DIBP) has rolled out new technologies to streamline and strengthen border operations. Departure SmartGates are currently in use at all international airports in Australia for processing passengers leaving the country. Passengers using Departure SmartGates are required to place their outgoing passenger card in the drop boxes located near the Departure SmartGate rather than handing them to Australian Border Force officers.

17 Coinciding with the roll-out of Departure SmartGates there has been an increase in outgoing passenger cards not being collected due to passengers failing to place their cards into the drop boxes. The ABS and DIBP are continually working together to mitigate this issue and to minimise the impact on data quality.

18 The ABS has introduced a new method to the Overseas Arrivals and Departures (OAD) system. The changes have led to revisions in OAD data as published in Overseas Arrivals and Departures, Australia (cat. no. 3401.0) from October 2014 onwards when missing passenger cards increased for various reasons. These revisions have had a flow on effect on preliminary NOM for December quarter 2014 to September quarter 2015 and consequently ERP for the same quarters. The revisions were minimal and were first published in the December 2015 release of Australian Demographic Statistics (cat. no. 3101.0) published on 23 June 2016.

19 For further information on the improvements to NOM estimation and changes to the revision schedule for NOM, see the Information Paper: Improving Net Overseas Migration Estimation, Mar 2010 (cat. no. 3412.0.55.001). For further information on the '12/16 month rule' methodology see the Technical Note: '12/16 month rule' Methodology for Calculating Net Overseas Migration from September quarter 2006 onwards in Migration, Australia, 2009-10 (cat. no. 3412.0). For more detailed information, see:
Preliminary NOM estimates

20 Preliminary estimates of NOM are required six months after the reference quarter for the production of quarterly estimates of the population of Australia, and the states and territories. At that time, complete traveller histories for the 16 months following a reference quarter cannot be produced. Since September quarter 2008, migration adjustments have been applied based on changes between intended and actual duration of stay from final NOM estimates one year earlier for travellers with similar characteristics. These characteristics include their 'initial category of travel', age, country of citizenship, and state/territory of usual/intended residence. The adjustments account for differences between their intended duration of stay and their actual duration of stay.

Final NOM estimates

21 It is with final NOM estimates that the '12/16 month rule' can be fully applied. A traveller's actual duration of stay can only be calculated when data on overseas movements become available for the 16 months following a reference period. Final NOM estimation methods use a traveller's actual duration of stay in or out of Australia to determine inclusion or exclusion from NOM estimates and consequently ERP estimates.


Diplomatic personnel

22 Australia's ERP and estimates of NOM include all people, regardless of nationality or citizenship, who usually live in Australia, with the exception of foreign diplomatic personnel and their families. Therefore, foreign diplomatic personnel and their families are considered out of scope and were removed from NOM estimates from 1 July 2006. The previous methodology for estimating NOM was unable to exclude diplomatic personnel and their families.


Net interstate migration

23 Interstate migration is a key determinant of the accuracy of state and territory population estimates. Data on interstate migration cannot be directly estimated. Instead, post-censal estimates of interstate migration are modelled using administrative by-product data. Currently, the data used by the ABS are information on interstate changes of address from Medicare Australia and the Department of Defence in the case of the military. The Medicare-based model used for generating post-censal estimates of interstate migration is largely superseded when new Census information becomes available.

24 When Census data on interstate movement become available, part of the process of rebasing ERPs for states and territories is the re-derivation of interstate migration for the intercensal period. The overall approach is to minimise state preliminary intercensal difference using data analysed from the Census questions concerning an individual's place of residence one year ago, five years ago and on Census night. When new Census data are available, interstate migration estimates for the intercensal period are replaced with estimates derived from Census data on place of usual residence five years ago if these reduce preliminary intercensal difference. These estimates are then scaled to sum to zero at the Australian level. A similar process is carried out for the year prior to the Census, using Census data on place of usual residence one year ago. The difference between the original interstate migration estimates and the rebased estimates is apportioned across all quarters, movement categories, ages and sex categories in the intercensal period in order to minimise quarterly change.

25 Changes to the model with updated expansion factors based on Census and other Medicare data are applied after each Census. Expansion factors are used to account for an undercoverage of Medicare data by various ages and sex. The current model is essentially unchanged from the model used to estimate interstate migration between 2006 to 2011 but for updated expansion factors based on the 2011 Census. The model includes the following characteristics:
  • Medicare data is lagged by three months (both for calculating expansion factors and for estimating progressive quarters of interstate migration);
  • smoothed inputs used to produce expansion factors (i.e. Census, Medicare and multiple movers data were smoothed);
  • capping applied to expansion factors;
  • expansion factors applied to males aged 19 to 32 years and females aged 19 to 25 years (this differs to the age range used in the 2006-11 method); and
  • no smoothing applied to the expansion factors.

26 The previously modelled data for the period September 2006 to June 2011 has been finalised based on data from the 2011 Census. All data from September 2011 onwards is modelled on 2011 Census expansion factors.

27 For more detailed information on the changes to the model see Information Paper: Review of Interstate Migration Method, March 2014 (cat. no. 3412.0.55.003).

28 Due to the fact that the Medicare data source is an indirect measure of interstate migration, the post-censal quarterly estimates of interstate migration have long been considered the weakest measure of the components of population change at the state and territory level. For further information on the process of estimating interstate migration and the administrative data used, see:

Defence force adjustment

29 Medicare theoretically covers all Australian usual residents as well as those non-Australian residents granted temporary Medicare registration. However, there are a range of Australian usual residents who do not access the Medicare system, primarily due to access to alternative health services. One group is the military. As such, estimates of interstate migration produced from the interstate migration model described in the Information Paper: Review of Interstate Migration Method, March 2014 (cat. no. 3412.0.55.003) are adjusted to compensate for defence force movements not covered by Medicare. These adjustments are estimated using counts of defence force personnel by age, sex and state/territory, obtained from the Department of Defence, with 70% of any change in quarterly defence numbers assumed to be due to interstate migration not otherwise covered by the model.


ESTIMATES AND PROJECTIONS OF ABORIGINAL AND TORRES STRAIT ISLANDER POPULATION

30 The standard approach to population estimation is not possible for determining the population of Aboriginal and Torres Strait Islander Australian. There are two primary reasons for this: the significant volatility in Aboriginal and Torres Strait Islander Census counts between censuses which cannot be attributed to demographic factors (i.e. the difference cannot be fully accounted for by natural increase and migration over the intercensal period); and the quality of data on births, deaths and migration specific to Aboriginal and Torres Strait Islander people. As a result, a method based on the use of life tables and rates of net interstate migration derived from the Census is used to backcast the series. Aboriginal and Torres Strait Islander estimates, based on the 2011 Census for the period 1996 to 2011, and projections from 2012 to 2026 are available in Estimates and Projections, Aboriginal and Torres Strait Islander Australians, 2001 to 2026 (cat. no. 3238.0). Three main projection series were produced with assumptions as follows. Projections Series A assumes: constant fertility rates; 2% annual increase in paternity rates (where the father of a child is Aboriginal or Torres Strait Islander but the mother is not); life expectancy at birth increasing by 0.5 years per year for males and 0.45 years per year for females, reaching 76.5 years for males and 80.4 years for females by 2026; levels of interstate migration as observed in the 2011 Census; and zero net overseas migration. Projection Series B assumes: an annual decrease of 0.5% in fertility rates; 1% annual increase in paternity rates; life expectancy at birth increasing by 0.3 years per year for males and 0.25 years per year for females, reaching 73.5 years for males and 77.4 years for females by 2026; levels of interstate migration as observed in the 2011 Census; and zero net overseas migration. Projection Series C assumes: an annual decrease of 1.0% in fertility rates; constant paternity rates; life expectancy at birth increasing by 0.2 years per year for males and 0.15 years per year for females, reaching 72.0 years for males and 75.9 years for females by 2026; levels of interstate migration as observed in the 2011 Census; and zero net overseas migration.


METHOD FOR DEFINING RESIDENTS TEMPORARILY OVERSEAS

31 The ABS has improved the measure of net overseas migration by expanding the Australian residence criteria from a 12/12 months rule to a 12/16 months rule. This has implications for the measurement of residents temporarily overseas (RTOs) on Census night due to the change in residence criteria mentioned above. A final measure of RTOs can only be obtained 21 months after Census night, when actual traveller behaviour, and each traveller's true residence status on Census night (according to 12/16 month rule) can be observed. For further information on the improved measure of net overseas migration see:

POPULATION PROJECTIONS

32 Population projections presented in this release are not predictions or forecasts. They are an assessment of what would happen to Australia's population if the assumed levels of components of population change - births, deaths and migration - were to hold in the future.

33 The ERP at June 2012 based to the 2011 Census is the base for the projections series. Projections off the 2011 Census based ERP were released on 26 November 2013 in "Population Projections, Australia, 2012 (base) to 2101" (cat. no. 3222.0). The three series presented in this release, and their assumptions are as follows:

34 Series A - assumes the Total Fertility Rate (TFR) will reach 2.0 babies per woman by 2026 and then remain constant, life expectancy at birth will experience continued improvement with increases from 2009-11 levels of 0.25 and 0.19 years each year for males and females respectively until 2060-61 (reaching 92.1 years for males and 93.6 years for females), NOM will increase to 280,000 people per year by 2020-21 and remain constant thereafter, and relatively large net interstate migration gains for some states and territories, corresponding to relatively large losses for other states and territories.

35 Series B - assumes the TFR will decline to 1.8 babies per woman by 2026 and then remain constant, life expectancy at birth will experience declining improvement with increases from 2009-11 levels of 0.25 and 0.19 years each year for males and females respectively until 2015-16 after which life expectancy will continue to increase at declining rates (reaching 85.2 years for males and 88.3 years for females by 2060-61), NOM will increase to 240,000 people per year by 2020-21 and remain constant thereafter, and medium net interstate migration gains for some states and territories, and medium losses for others.

36 Series C - assumes the TFR will decline to 1.6 babies per woman by 2026 and then remain constant, life expectancy at birth will experience declining improvement with increases from 2009-11 levels of 0.25 and 0.19 years each year for males and females respectively until 2015-16 after which life expectancy will continue to increase at declining rates (reaching 85.2 years for males and 88.3 years for females by 2060-61), NOM will increase to 200,000 people per year by 2020-21 and then remain constant thereafter, and relatively small net interstate migration gains for some states and territories and small losses for others.

37 For additional series and information (e.g. age, sex, states/territories and greater capital cities/balances of state), see Population Projections, Australia, 2012 (base) to 2101 (cat. no. 3222.0).


HOUSEHOLD PROJECTIONS

38 The ABS uses a propensity method to project numbers of households, families and persons in different living arrangements. The method identifies propensities (proportions) from the Census of Population and Housing for people to belong to different living arrangement types. Trends observed in the propensities over the last four censuses are assumed to continue into the future, and applied to a projected population (see Series B, Population Projections, Australia, 2012 (base) to 2101 (cat. no. 3222.0)). Numbers of households and families are then derived from the projected living arrangements of the population.

39 Data presented in table 18 are not intended as predictions or forecasts, but are illustrations of growth and change in the numbers of households which would occur if the assumptions about future trends in living arrangements were to prevail over the projection period. For more information see Household and Family Projections, Australia, 2011 to 2036 (cat. no. 3236.0). Household projections presented in this release are based on the 2011 Census.


CONFIDENTIALITY

40 The Census and Statistics Act, 1905 provides the authority for the ABS to collect statistical information, and requires that statistical output shall not be published or disseminated in a manner that is likely to enable the identification of a particular person or organisation. This requirement means that the ABS must take care and make assurances that any statistical information about individual respondents cannot be derived from published data.

41 Some techniques used to guard against identification or disclosure of confidential information in statistical tables are suppression of sensitive cells, and random adjustments to cells with very small values. To protect confidentiality within this release, some cell values may have been suppressed and are not available for publication (np) but included in totals where applicable. In these cases, data may not sum to totals due to the confidentialisation of individual cells.


ROUNDING

42 In this release, population estimates and their components have sometimes been rounded. Where figures have been rounded, discrepancies may occur between sums of component items and totals.


ACKNOWLEDGMENT

43 ABS statistics 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 in 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.


USE OF POPULATION ESTIMATES IN REPORTING

44 The ABS provides regular explanatory information to support users in understanding both population trends and methodological changes, but does not comment on the specific use (or otherwise) of official population estimates by other organisations or individuals.

45 Population estimates are used extensively within the Australian community, including in a range of agreements. Although the ABS acknowledges that the official population estimates and changes in these estimates are specifically referenced in various agreements, it neither endorses nor disapproves of the terms of the agreements and decisions made by parties in relation to those agreements. In addition, the ABS does not provide a position on disputes arising from the interpretation of terms of an agreement that reference official population estimates.


RELATED PRODUCTS

46 Other ABS products which may be of interest to users include:

ADDITIONAL STATISTICS AVAILABLE

47 As well as the statistics included in this and related products, the ABS may have other relevant data available on request. Inquiries should be made to the National Information and Referral Service on 1300 135 070.

48 ABS products and publications are available free of charge from the ABS website <http://www.abs.gov.au>. Click on Statistics to gain access to the full range of ABS statistical and reference information.

49 Statistics of net overseas migration and related data are also published regularly by DIBP <http://www.border.gov.au> (see the Department’s quarterly publication The Outlook for Net Overseas Migration).