




































AUSTRALIAN POPULATION STUDIES  2019 | Volume 3 | Issue 1 | pages 40-56 

 

© Wilson 2019. Published under the Creative Commons Attribution-NonCommercial licence 3.0 Australia (CC BY-NC 3.0 
AU). Journal website: www.australianpopulationstudies.org 

 

Introductory Guide 

An introduction to population 
projections for Australia 

Tom Wilson*  Charles Darwin University 

* Email: tom.wilson@cdu.edu.au. Address: Northern Institute, Charles Darwin University, Darwin, NT 

0909 

Paper received 30 January 2019; accepted 19 April 2019; published 27 May 2019 

Abstract 

Background 

Population projections for Australia are produced by many organisations. They differ in projected 

population numbers, methods used, level of output detail, temporal extent, frequency of revision, 

quality and purpose, and they are not always easy to find. 

Aims 

This paper provides a brief guide to many of the population projections prepared for Australia in 

recent years. It gives an overview of projection methods and selected results, a brief commentary on 

key aspects of the projections, and shows readers where to find more data and information. 

Data and methods 

Projections data were obtained from the various organisations producing projections. They are 

presented in order of spatial detail: national scale, States and Territories; large sub-state regions; and 

then local and small areas. 

Results 

The ABS and State and Territory Governments are the main producers of population projections and 

forecasts in Australia, and generally these projections are good quality. They cover a wide variety of 

spatial scales from the national level to local areas, such as SA2s. A great deal of projections data and 

information is now freely available online. 

Conclusions 

Population projections and forecasts can be very useful data for a wide variety of planning, policy 

and research purposes. But it is important to be aware of their limitations. 

Key words 

Population projections; population forecasts; projections data; Australia 

 

  

http://www.australianpopulationstudies.org/
mailto:tom.wilson@cdu.edu.au


Australian Population Studies 3 (1) 2019 Wilson  41 

1. Introduction 

Population projections are calculations of population beyond the latest population estimate based 

on assumptions about the future of fertility, mortality and migration. Projected populations, and 

sometimes also projected births, deaths and migration, are used in a wide variety of planning, policy 

development, service delivery, market assessment, and research activities, as well as in public 

debates about Australia’s future. For example: 

 State and Territory governments formulate urban and regional plans which take into account the 

future demand for housing, schools, hospitals, public transport, and so on; 

 utility companies wish to plan for future electricity, water and sewage treatment needs; 

 the Commonwealth Government uses projections to assess the likely costs of future health 

provision and aged pensions (as shown in its Intergenerational Reports, e.g. Australian Treasury 

2015); 

 the Australian Electoral Commission uses short-term projections of enrolments to vote to adjust 

electoral boundaries to ensure constituencies are likely to contain roughly equal numbers of 

electors (e.g. Australian Electoral Commission 2017). 

Projections are also sometimes used as interim population estimates for the present because official 

Estimated Resident Populations (ERPs) are published some time after their reference dates (between 

around 6 and 15 months depending on geographical scale and level of demographic detail). 

Population projections for Australia are produced by many organisations. They differ in projected 

population numbers, methods used, level of output detail, temporal extent, frequency of revision, 

quality, and purpose. And they are not always easy to find on the web. The aim of this paper is to 

provide a brief guide to many of the population projections prepared for Australia in recent years. It 

gives an overview of methods employed, data outputs, where projections data and accompanying 

information can be obtained, along with a few comments about the projections. National projections 

are covered first, followed by those for States and Territories, major sub-state regions, and then local 

and small areas. Details of the projections are not presented and interested readers are encouraged 

to look up the web resources listed in the paper to find out more. Projections of other demographic 

variables, such as households, living arrangements, dwellings, populations by Indigenous status, 

school enrolments and so on, are outside the scope of the paper. Be aware that all projections 

mentioned in the paper (along with URLs) refer to those publically available as of 30th April 2019. 

Projections are revised regularly and may have been updated since the time this article was finalised. 

Before proceeding any further I define the meanings of some common projections terms such as 

projection horizon, jump-off year, and the difference between a projection and a forecast. These are 

listed in Box 1. 

 

  



42 Wilson  Australian Population Studies 3 (1) 2019 

Box 1: Projections terminology 

Jump-off year: the starting year of population projections; the year in which they ‘jump off’ into the 

demographic future. It is sometimes also known as the launch year. 

Population estimate: the population for a past or current point in time derived from demographic 

information available for that time. 

Population projection: a calculation of population beyond the jump-off year based on certain 

assumptions about the future of fertility, mortality and migration (and sometimes other variables). 

Projection series: a projection with a specified combination of fertility, mortality and migration 

assumptions (often labelled low, medium, or high; or sometimes labelled with letters and numbers). 

Projection scenario: a projection based on a vision, story, or set of particular circumstances (e.g. 

restrictive immigration policy scenario; major new employer scenario; mine closure scenario). 

Population forecast: a population projection deemed to be the most likely future population; a 

prediction. (Therefore all forecasts are projections, but many projections are not forecasts). 

Projection/forecast horizon: the time period between the jump-off year and the final year of the 

projections/forecasts. 

Projection assumptions: data inputs to the projection calculations which usually include the assumed 

future of fertility, mortality, and migration (and sometimes other input variables, e.g. housing 

developments). If more broadly defined, projection assumptions also implicitly or explicitly include 

qualitative elements, such as expectations about future immigration policy, and the absence of major 

disasters. 

Probabilistic projections/forecasts: projections/forecasts which are expressed as a range of future 

populations, often with prediction intervals. Prediction intervals consist of a range with a probability 

of future population lying within that range. 

Deterministic projections/forecasts: projections/forecasts which are expressed as a single set of 

values; most national projections and almost all subnational projections are of this type. 

Net migration: The value of inward migration minus outward migration, such as Net Interstate 

Migration (NIM) which is interstate in-migration minus interstate out-migration, or Net Overseas 

Migration (NOM) which is immigration (which the Australian Bureau of Statistics (ABS) terms NOM 

arrivals) minus emigration (NOM departures). 

Directional migration: Flows of migration from one country or region to another; for example, 

migration from overseas to Australia (immigration), or from New South Wales to other jurisdictions 

within Australia (interstate out-migration). 

Source: the author 

  



Australian Population Studies 3 (1) 2019 Wilson  43 

2. Population projections for Australia 

2.1. National population projections 

The best known population projections for Australia are those produced by the Australian Bureau of 

Statistics (ABS) in their Population Projections, Australia publication. Updated every five years, the 

most recent ABS projections were released in November 2018 (ABS 2018a). These projections start 

from a jump-off year of 2017 and cover a projection horizon of almost 50 years, ending in 2066. The 

ABS applies a standard cohort-component model1 incorporating directional migration flows 

(immigration and emigration) constrained to total Net Overseas Migration (NOM) assumptions (ABS 

1999). Most emphasis is placed on three main projection series – A, B and C – which are often 

interpreted as high, medium and low series. A further 69 projection series with differing fertility, 

mortality and migration assumptions are also prepared and are available for download from the ABS 

website. Series B is generally interpreted by users to be a forecast, though ABS deliberately avoids 

the term ‘forecast’ and emphasises that all its future population numbers are merely projections. 

The Series B projection sees Australia’s population increasing from 24.6 million in 2017 to 42.6 

million by 2066, the result of a long-run Total Fertility Rate of 1.80, Net Overseas Migration of 

225,000 per annum, and modest and decelerating increases in life expectancy at birth (86.0 years for 

females and 83.0 years for males by the end of the projection horizon). The projected population 

growth rate gradually declines into the future because population ageing results in the number of 

deaths rising slightly faster than births, and because a fixed level of Net Overseas Migration in the 

context of an increasing population represents a falling crude rate of net migration.  

The projection assumptions are based primarily on recent levels of fertility and Net Overseas 

Migration observed over the last few years, and the small increases in life expectancy observed in 

recent years. These trends are assumed to continue. Interestingly, life expectancy at birth is expected 

to rise by very little and is less optimistic than in the previous set of ABS projections (ABS 2013), and 

by the 2060s is over 2 years of life lower. Some users may wish to download projection series 26 

which incorporates the ABS high life expectancy assumptions (increasing to 87.7 years and 89.2 years 

for males and females respectively by 2065-66). The Series 26 projection is 1.1 million higher than 

Series B by 2066, nearly all of which is in the 65+ age group. Figure 1 illustrates the latest ABS Series 

B projection alongside several others for Australia, while Figure 2 presents some of the assumptions 

on which those projections were based. Box 2 includes URLs which will take readers to these and 

other projections mentioned in the paper. 

The United Nations Population Division updates population projections for Australia every two years 

as part of its World Population Prospects publication (UN 2017a). This publication contains 

projections for all countries of the world (except the very smallest) along with projections for the 

world as a whole. The projections in the 2017 Revision of World Population Prospects start from a 

jump-off year of 2015 and extend all the way out to 2100. The UN uses a cohort-component model 

with five year age groups which proceeds forward in five year intervals; overseas migration is 

generally projected as net migration numbers due to the lack of reliable data on immigration and 

                                                           
1
 For basic introductions to the cohort-component model see Rowland (2003) chapter 12, or Smith et al. (2013) 

chapters 3 to 7. For a description of subnational and multiregional cohort-component models see Rees (1997) 
and the review in Rees et al. (2015). 



44 Wilson  Australian Population Studies 3 (1) 2019 

emigration flows for all countries (UN 2017b). The demographic transition model (Dyson 2010) 

provides the over-arching theoretical framework for setting fertility and mortality assumptions, so 

that all countries are assumed to progress through the transition from high to low fertility and 

mortality rates. Net Overseas Migration is assumed to remain constant until 2045-50 if recent 

numbers have been stable, and then decline to half that number by 2095-2100. This approach was 

taken because it “represents a compromise between the difficulty of predicting the levels of 

immigration or emigration for each country of the world over such a far horizon, and the recognition 

that net migration is unlikely to reach zero in individual countries” (UN 2017b p. 30). 

The UN’s projection assumptions for Australia consist of a long-run TFR varying slightly between 1.76 

and 1.80, life expectancy reaching 87.3 years for males and 90.5 years for females by 2060-65 (and 

91.5 and 94.7 years respectively by 2095-2100), and Net Overseas Migration set to an annual average 

of 150,000 from 2020 to 2050, declining gradually to 75,000 by 2095-2100. The UN assumptions for 

mortality and migration differ considerably from those of the ABS Series B projection, with the UN 

selecting much higher life expectancy and much lower Net Overseas Migration levels. According to 

the UN’s main series projection, Australia’s population is projected to increase from 23.8 million in 

2015 to 41.8 million by 2100. By 2066 it is expected pass 36.6 million (7 million lower than the ABS 

Series B projection). Differences with ABS projections are largely due to NOM assumptions and are 

particularly noticeable in the 0-14 and 15-64 age groups (Figure 1b). The UN projections comprise 

nine variants as well as probabilistic projections created from probabilistic fertility and mortality 

inputs (though, interestingly, not probabilistic overseas migration inputs). Outputs from, and 

information about, these alternative projections can be found at the webpage listed in Box 2. 

Intergenerational reports are prepared by the Australian Treasury every few years, with the most 

recent being the 2015 report (Australian Treasury 2015). The purpose of these reports is to “assess 

the long-term sustainability of current Government policies and how changes to Australia’s 

population size and age profile may impact economic growth, workforce and public finances” 

(Australian Treasury 2015 p. xxiii). The assessment is underpinned by a series of demographic and 

economic projections looking ahead over the next four decades. The population projections are 

prepared with a standard cohort-component model. Treasury’s projection for Australia’s population 

in 2055 is 39.7 million, the result of a Total Fertility Rate of 1.90, life expectancy at birth increasing to 

87.5 years for males and 90.1 years for females by 2050, and long-run Net Overseas Migration levels 

of 215,000 per annum. 

Population projections for Australia are also produced by other organisations and individuals as 

occasional or one-off exercises. Three examples are mentioned here. The Productivity Commission 

created population projections as part of the report An Ageing Australia (Productivity Commission 

2013). Their projections from 2012 to 2060 put the national population at 38.3 million by the end of 

the projection horizon. Lutz et al. (2018) created projections for most countries of the world by 

educational status from 2015 to 2100. Their medium scenario has Australia’s total population at 32.5 

million by 2050 and 43.6 million by 2100. Bell et al. (2011) prepared probabilistic population 

forecasts for Australia from 2010 to 2051. Their forecasts included a 95% prediction interval for 

Australia’s total population in 2051 spanning 29.4 to 43.0 million, with the median of the distribution 

at 36.1 million. 



Australian Population Studies 3 (1) 2019 Wilson  45 

 

(a) Projections of Australia’s total population 

 

(b) Projections of Australia’s population aged 0-14, 15-64 and 65 years and over 

Figure 1: Some recent projections of Australia’s population 

Notes: ERP = Estimated Resident Population 

Sources: ABS (2018a; 2018b), UN (2017a), Australian Treasury (2015) 

  



46 Wilson  Australian Population Studies 3 (1) 2019 

 

(a) Net Overseas Migration assumptions 

 

(b) Life expectancy at birth assumptions 

 

(c) Total Fertility Rate assumptions 

Figure 2: Assumptions behind some recent projections of Australia’s population 

Notes: TFR = Total Fertility Rate; e0 = life expectancy at birth 

Sources: ABS (2014; 2018a; 2018b), Human Mortality Database (2017), UN (2017a), Australian Treasury (2015) 



Australian Population Studies 3 (1) 2019 Wilson  47 

2.2. Projections at the State and Territory scale 

The ABS and State and Territory Governments all produce population projections at the State and 

Territory scale every few years. ABS State and Territory projections are published as part of its 

Population Projections, Australia publication (ABS 2018a). These projections have a high profile 

because they are published by the national statistical office. Because they are produced using a 

consistent method, and have net interstate migration summing to the logical value of zero across all 

jurisdictions, the projections are useful for analyses involving all States and Territories across 

Australia. State and Territory Governments produce projections for their own State/Territory as a 

whole, plus projections for a variety of sub-state geographies, with updates mostly prepared every 2 

to 5 years. These projections are important because government departments within that State or 

Territory are required to use them in their analysis, planning and budgeting. Data and information on 

all these projections can be obtained from the URLs listed in Box 2. 

The ABS projects State and Territory populations with a cohort-component model which is similar to 

the national-scale model but with the addition of interstate migration. Interstate in- and out-

migration flows are handled as directional (rather than net) migration flows but are constrained to 

be consistent with assumed Net Interstate Migration (NIM) totals. The model is not a fully multi-

regional model with flows between each State/Territory and every other, but a bi-regional type 

which handles in- and out-migration flows between each State/Territory and the remainder of the 

country (ABS 1999; Wilson and Bell 2004). In the latest set of ABS projections medium variant NIM 

assumptions are based on the average NIM values of the last 10 years. Series B State and Territory 

population projections are illustrated in Figure 3 alongside those produced by State and Territory 

Governments. A log scale is used in the graph to clearly show the projected trends of the less 

populous states and territories. 

All State and Territory Governments make use of cohort-component projection models of various 

types. Most projection models use directional (rather than net) migration, which is conceptually 

better and avoids implausible outputs. Some models work with five year age groups and projection 

intervals, though most use single year ages and intervals; some State and Territory Governments 

produce only one set of projections while others produce multiple series. Medium series projections 

often use assumptions which deliver similar results to the ABS Series B projections in terms of total 

population, which is probably a mix of similar thinking and a desire to avoid having to explain to 

users why their projections are so different. 

The New South Wales Department of Planning and Environment produces official NSW Government 

population projections for NSW. High, medium and low series are produced. The latest projection 

covers a horizon of 2011 to 2041 and the medium series puts the NSW population at 10.46 million by 

the end of that period (NSW Department of Planning and Environment 2016). These projections are 

fractionally lower than those of the ABS. 

The Department of Environment, Land, Water and Planning in Victoria produces population 

projections for its Victoria in Future publication. Only one projection series is published. The latest 

‘Victoria in Future 2016’ projections cover the period 2011 to 2051 at the State level and show 

Victoria’s population increasing from 5.54 million to 10.09 million over those four decades (Victorian 



48 Wilson  Australian Population Studies 3 (1) 2019 

Department of Environment, Land, Water and Planning 2016). These are a little lower than the ABS 

Series B projections. 

The Queensland Government Statistician’s Office prepares the official population projections for that 

State. High, medium and low series are published. Its latest projections were published in 2018 and 

extend from 2016 to 2066. The medium series projections indicate growth from 4.85 million to 9.51 

million over the projection horizon (Queensland Government Statistician’s Office 2018), showing 

marginally higher growth than the ABS Series B projection. 

Western Australia Tomorrow is the publication produced by the Department of Planning, Lands and 

Heritage containing population forecasts for Western Australia (Western Australian Planning 

Commission 2018). These projections are unusual in that they are formally labelled ‘forecasts’ and 

are produced by a form of probabilistic cohort-component model. Within the probabilistic forecasts 

five alternative projection trajectories are distinguished, labelled bands A, B, C, D and E. The latest 

Band C (medium series) forecasts envision WA’s population growing from 2.35 million in 2011 to 3.25 

million by the end of the projection horizon in 2031 (Western Australian Planning Commission 2018), 

which is slightly higher than ABS Series B projection. 

Tasmania’s latest population projections were published recently and include high, medium and low 

series. The medium series show the State’s population growing from 522,000 in 2017 to 577,000 by 

2067 (Tasmanian Department of Treasury and Finance 2019). The projected trajectory of Tasmania’s 

total population is close to the latest ABS Series B projection.  

The Northern Territory’s projected population is calculated as the sum of separate projections for its 

Indigenous and non-Indigenous residents, a feature which is unique amongst the State and Territory 

Government population models. The cohort-component model incorporates overseas and interstate 

migration flows, permits changes to reported Indigenous status over time, and allows the Indigenous 

status of newly-born babies to differ from those of their mothers. The four projection series are 

labelled Main, Current, High and Low. The main series from the latest projections has the population 

growing from 246,000 in 2016 to 352,000 by 2046; the Indigenous population is expected to increase 

from 75,000 in 2016 to 104,000 by 2046 while the non-Indigenous population is projected to grow 

from 171,000 to 247,000 over the same projection horizon (NT Department of Treasury and Finance 

2019). The NT’s total population is a little under the ABS Series B projection until the 2040s. 

The current Australian Capital Territory Government population projections start from a jump-off 

year of 2017 and extend out to 2058 (ACT Government 2019). Only one projections series was 

published. The projections indicate that the population will increase from 412,000 in 2017 to 703,000 

by 2058, which is a very similar growth trajectory to the latest ABS Series B projections. 

 



Australian Population Studies 3 (1) 2019 Wilson  49 

 

Figure 3: Some recent projections of State and Territory populations 

Notes: State and Territory Government medium/main series projections are shown. 

Sources: ABS (2018a), NSW Department of Planning and Environment (2016), Victorian Department of 

Environment, Land, Water and Planning (2016), Queensland Government Statistician’s Office (2018), Western 

Australian Planning Commission (2018), Tasmanian Department of Treasury and Finance (2019), NT 

Department of Treasury and Finance (2019), ACT Government (2019). 

 

2.3. Projections for large sub-state regions 

The ABS projections in Population Projections, Australia include projections for Greater Capital City 

Statistical Areas and balance of State/Territory regions. They are produced using a cohort-

component model projecting internal migration flows in and out of each region constrained to a total 

net internal migration assumption. The latest Series B projections suggest an increasing 

concentration of population in Australia’s metropolitan regions over the coming decades (ABS 

2018a). The combined population of the capital cities is expected to grow from 16.6 million in 2017 

(67.3% of the national population) to 32.1 million by 2066 (75.3%). By the end of the projection 

horizon Sydney and Melbourne are projected to be 9.7 and 10.2 million, respectively, with Brisbane 

the next largest at 4.8 million. The greatest proportional increase, however, is projected for Greater 

Darwin (149,000 in 2017 and 333,000 in 2066). Projections of metropolitan growth such as these 

tend to gain lots of media attention, but the demographic outcomes for other regions can look very 

different. The Rest of South Australia and Rest of Tasmania are projected to decline in population 

and experience considerable amounts of population ageing. 



50 Wilson  Australian Population Studies 3 (1) 2019 

Some State and Territory Government projections are published for Greater Capital City Statistical 

Areas as well as for other large sub-state regions. In some cases these projections are created 

directly, but in others they are created by building up from smaller geographical areas. Table 1 lists 

the large sub-state regions for which projections are published in the current sets of projections. In 

Queensland, for example, projections are published for Brisbane Greater Capital City Statistical Area 

and all other SA4 regions of the State (Queensland Government Statistician’s Office 2018). Under the 

medium series projections Brisbane grows from 2.36 million in 2016 to 3.67 million by 2041 (which is 

very close to the latest ABS Series B projection). Population growth is anticipated for all other regions 

of Queensland with the exception of Queensland – Outback where the total population remains 

largely unchanged. 

Table 1: State and Territory Government projections for large sub-state regions 

State/Territory Sub-state regions 

NSW Projection Regions, defined as aggregations of local government areas;  

Local Health Districts 

Vic Major Regions, defined as Melbourne Greater Capital City Statistical Area and SA4 areas 

across the rest of the State 

Qld Brisbane Greater Capital City Statistical Area and SA4 regions across the rest of the 

State 

SA Statistical Divisions 

WA No large sub-state regions in the current projections output 

Tas No large sub-state regions in the current projections output 

NT Regions, defined as SA3 areas; SA4 regions  

ACT Districts, defined as SA3 areas 

Sources: See Figure 3. 

2.4. Projections for local and small areas 

For many users, local and small area population projections are the most useful. They inform 

planning, budgeting, and service delivery at the local scale, and small area projections can also be 

aggregated up to a variety of custom-defined regions. In some cases they can generate strong local 

reactions, such as objections from a mayor when projections show population decline or little 

growth, or protests from local community groups about anticipated rapid growth viewed as likely to 

adversely affect the character and quality of life of a local neighbourhood.  

The ABS does not produce local or small area projections as part of its official projections output 

(though it does prepare them as a consultancy on behalf of other organisations). The key producers 

of local and small area projections are State and Territory Governments who tend to publish Local 

Government Area (LGA) and/or SA2 area projections, as shown in Table 2. See Box 2 for URLs. Often 

local and small area projections in metropolitan regions are derived from cohort-component models 

linked to housing unit models (Foss 2002; Wilson 2011), which are based on assumptions about 

expected future dwelling growth. The incorporation of dwelling data in these projections can result 

in substantially different outputs compared to trend-based projections. For example, the populations 

of urban fringe areas experiencing considerable increases in the amount of residential land becoming 

available will not be projected accurately from trend-based models. But reasonable projections may 

be obtained via housing-unit models if the land development and dwelling forecasts are about right. 



Australian Population Studies 3 (1) 2019 Wilson  51 

Table 2: State and Territory Government projections for local and small areas 

State/Territory Areas 

NSW Local Government Areas 

Vic Local Government Areas; Victoria in Future Small Areas (aggregations and modifications 

of SA2 areas which nest into LGAs) 

Qld Local Government Areas; SA2 areas 

SA Local Government Areas; Statistical Local Areas 

WA SA2 areas 

Tas Local Government Areas 

NT No local or small areas in the current projections output 

ACT SA2 areas 

Sources: See Figure 3 

A variety of other organisations also prepare local and small area projections from time to time. The 

Commonwealth Department of Social Services (2014) has published SA2 area projections by age and 

sex for the whole of Australia. They were prepared by the ABS as a consultancy and cover a 

projection horizon of 2012 to 2027, so are a little old now. Their main advantage is the use of a 

common method and data inputs across the whole country. However, the migration assumptions are 

purely trend-based so projections for SA2 areas within metropolitan regions should be used with 

caution beyond just a few years into the projection horizon. This also applies to certain non-

metropolitan local areas, such as mining towns (e.g. Taylor et al. 2014). 

The Australian Electoral Commission obtains short-term SA1 area population projections from time 

to time (usually as a consultancy from the ABS). They are used to calculate likely numbers of enrolled 

electors over the next few years for the purpose of electoral boundary redistributions. The 

enrolment projections are generally made available, but not the population projections on which 

they are based (e.g. Australian Electoral Commission 2017). 

Several consulting firms also produce local and small area projections. For example, id prepares 

projections for many local government areas which are freely available if councils place them on 

their websites. id also creates smaller geographical areas in its Small Area Forecast Information (SAFI) 

product (id 2018). Pitney Bowes produces SA1 area population projections (Pitney Bowes 2018). The 

small area projections are prepared on a consulting basis and must be paid for. 

3. Concluding remarks 

Population projections and forecasts can be very useful inputs to decision-making, policy 

formulation, budgeting, and planning. But it is important to be aware of their limitations. Strictly, 

population projections, as statements about future population under certain assumptions, are 

correct provided they have been calculated correctly. This is the case most of the time – but not 

always. However, population forecasts will almost certainly turn out to be in error to some extent. 

This can be due to a suboptimal choice of projection model, subsequent revisions to the jump-off 

population and historical demographic components, random noise, and deviations in actual fertility, 

mortality and migration from the projection assumptions. As a general rule: 

 the further a forecast extends into the future the greater the error;  

 the smaller the population the greater the error; and  



52 Wilson  Australian Population Studies 3 (1) 2019 

Box 2: Selected population projections for Australia and where to obtain them 

Population projections produced by the Commonwealth Government  

Population Projections, Australia – ABS 

   http://www.abs.gov.au/ausstats/abs@.nsf/mf/3222.0  

Intergenerational Report – Australian Treasury 

   https://treasury.gov.au/intergenerational-report/  

An Ageing Australia – Productivity Commission 

   https://www.pc.gov.au/research/completed/ageing-australia  

SA2 population projections – Department of Social Services  

   https://www.gen-agedcaredata.gov.au/Resources/Access-data/2014/August/Population-projections,-

2012-(base)-to-2027-for-al  

Population projections produced by State and Territory Governments 

NSW: Population projections – Department of Planning & Environment 

   https://www.planning.nsw.gov.au/projections  

Vic: Victoria in Future – Department of Environment, Land, Water & Planning 

   https://www.planning.vic.gov.au/land-use-and-population-research/victoria-in-future-2016  

Qld: Population Projections – Queensland Government Statistician’s Office 

   http://www.qgso.qld.gov.au/subjects/demography/population-projections/index.php  

SA: Department of Planning, Transport and Infrastructure 

 https://www.saplanningportal.sa.gov.au/data_and_research/population_projections_and_demographics  

WA: WA Tomorrow – Department of Planning, Lands and Heritage 

   https://www.dplh.wa.gov.au/information-and-services/land-supply-and-demography/western-

australia-tomorrow-population-forecasts  

Tas: Population Projections – Department of Treasury & Finance 

   https://www.treasury.tas.gov.au/economy/economic-data/2019-population-projections-for-tasmania-

and-its-local-government-areas  

NT: Population Projections – Department of Treasury & Finance 

   https://treasury.nt.gov.au/dtf/economic-group/population-projections  

ACT: Population projections – Treasury and Economic Development Directorate 

   https://apps.treasury.act.gov.au/snapshot/demography/act  

Population projections produced by overseas organisations 

World Population Prospects – United Nations Population Division 

   https://population.un.org/wpp/  

Population projections by educational status – Wittgenstein Centre 

   http://dataexplorer.wittgensteincentre.org/wcde-v2/   

Population projections produced by consulting firms 

Many local and small area projections are produced by consulting firms. Summary data may sometimes 

be freely available but generally these projections must be paid for. Examples include: 

Small Area Forecast Information (SAFI) projections – id 

   https://home.id.com.au/services/population-forecasting/small-area-population-forecasts-safi/  

SA1 area projections – Pitney Bowes 

   https://www.pitneybowes.com/au/data/demographic-data/estimates-projections-australia.html  

Note: URLs correct as of 30th April 2019.  

http://www.abs.gov.au/ausstats/abs@.nsf/mf/3222.0
https://treasury.gov.au/intergenerational-report/
https://www.pc.gov.au/research/completed/ageing-australia
https://www.gen-agedcaredata.gov.au/Resources/Access-data/2014/August/Population-projections,-2012-(base)-to-2027-for-al
https://www.gen-agedcaredata.gov.au/Resources/Access-data/2014/August/Population-projections,-2012-(base)-to-2027-for-al
https://www.planning.nsw.gov.au/projections
https://www.planning.vic.gov.au/land-use-and-population-research/victoria-in-future-2016
http://www.qgso.qld.gov.au/subjects/demography/population-projections/index.php
https://www.saplanningportal.sa.gov.au/data_and_research/population_projections_and_demographics
https://www.dplh.wa.gov.au/information-and-services/land-supply-and-demography/western-australia-tomorrow-population-forecasts
https://www.dplh.wa.gov.au/information-and-services/land-supply-and-demography/western-australia-tomorrow-population-forecasts
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Australian Population Studies 3 (1) 2019 Wilson  53 

 the greater the volatility of migration the greater the error 

(Smith et al. 2013; Wilson et al. 2018). Forecast errors are often larger than many users realise. 

Projections and forecasts can also be subject to another form of error – misinterpretation and 

misreporting. Net Overseas Migration projections are regularly misinterpreted as immigration (which 

is only correct in the absence of emigration!). Sometimes population projections are interpreted as 

population targets or policies (which would only be correct if a projection had been expressly created 

as such). For example, the reporting of Australia’s population passing the 25 million milestone in 

2018 was reported by some news outlets (deliberately not cited) as “33 years ahead of schedule” 

based on ABS projections from the late 1990s, as if those ABS projections were part of a national 

population policy. 

Population projections are highly sensitive to input assumptions, and these can vary considerably 

from one projection to another (as Figure 2 shows). Generally assumptions do not attempt to predict 

trend changes or cyclical paths, but instead aim for a smooth trajectory through the middle of an 

undulating pattern. Assumptions are sometimes based on statistical models, and sometimes on 

judgement. In reality they often involve a mix of art and science. In Australia, overseas migration 

contributes the bulk of error in national population forecasts while at the state and regional scales 

both internal and overseas migration tend to contribute most of the error (Wilson 2007, 2012). The 

variability of overseas migration makes it especially challenging to forecast and there is no robust 

mathematical model available which has proven to give accurate migration forecasts, at least in the 

medium and long-term (Disney et al. 2015). The history of fertility forecasting is also not an 

unqualified success despite a large literature attempting to understand and forecast period and 

cohort fertility (Bohk-Ewald et al. 2018). Mortality forecasting at the national scale has been subject 

to a great deal of research attention and there are an ever increasing number of sophisticated 

models to choose from (Booth and Tickle 2008; Janssen 2018). Generally, errors in mortality 

forecasts are lower than those of fertility and migration. Nonetheless, mortality models are almost all 

extrapolative models. Should a major change in mortality trends occur, as appears to be the case in 

the US and UK at the moment, errors could be larger than in the past. 

Before using a set of projections, it is valuable to ask who prepared them and why. That may go some 

way to explaining the choice of projection assumptions and the way in which projection outputs are 

presented. No set of projections is ever completely objective and free of analysts’ judgments. For 

example, given the sensitivity about population decline in Australia, projections for local areas 

currently experiencing population decline sometimes err on the ‘optimistic’ side by showing much 

less decline, or even no decline, in the future. State/Territory projections may be influenced by the 

incumbent Government’s view on whether recent population growth is too high or too low, or an 

explicit population policy. Projections produced by consulting firms will sometimes reflect the 

assumptions, or aspirations, of the client. 

It is also sensible to conduct a quick assessment of the plausibility of any set of projections you are 

considering using (see also Smith et al. 2013 pp. 385-390; Wilson 2017). While most projections have 

been generated by good models and sensible assumptions, this is not universally the case. Treat 

projections which have been produced using models incorporating net migration numbers or net 

migration rates with caution (Rogers 1990; Wilson 2016). They have the potential to generate 



54 Wilson  Australian Population Studies 3 (1) 2019 

implausible or impossible outcomes. At the local level in growing urban regions, it is also worth 

checking that projections are based on anticipated housing developments. Be wary of purely trend-

based local area projections in such regions. Projected age-sex structures should generally evolve 

slowly and will often maintain characteristic peaks and troughs across the peak migration age groups 

(late teens to late 30s), as well as continued population ageing. For example, if a local population age 

structure has a large peak across the late teens and early twenties due to a higher education 

institution then you would expect that peak to be maintained in the projections. In addition, 

projected total population, births, deaths and migration flows should follow on smoothly from 

observed trends – unless there are good reasons for such changes. The projected age pattern of sex 

ratios should also change gradually in the projections. 

In summary, this paper has provided a brief guide to Australian population projections data at 

various geographical scales. It has introduced many (though not all) of the projections produced for 

Australia in recent years, and included some brief comments on the limitations of projections. It is 

hoped that the guide proves a useful starting point for exploring population projections data and 

understanding the context and broader processes involved in population projections preparation. 

Key messages 

 Population projections are calculations of population beyond the latest population estimate 

based on assumptions about the future of fertility, mortality and migration. 

 Population projections are used in planning, policy development, service delivery, market 

assessment, research activities, and public debate. 

 The ABS and State and Territory Governments are the main producers of population projections 

and forecasts in Australia.  

 A great deal of projections data and information is now freely available online (Box 2). 

 Be aware of the limitations of projections and forecasts. 

Acknowledgements 

I am grateful for the helpful comments on an earlier draft of this paper by Alison Taylor, Hitesh 

Khanna, ABS demography staff, and the anonymous reviewers. 

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