Chapter 4 - Projections of the demand-supply gap
- Key points
- Overview
- The gap between total demand and total supply in 2008
- The size of the gap in 2008
- Future changes in the demand-supply gap
- Medium demand and medium supply
- Sensitivity of estimates of the gap
- Other considerations
- Key indicators for demand-supply gap
Key points
- The gap between total underlying demand and total supply is conservatively estimated to be approximately 85,000 dwellings as at June 2008, taking into account information on homelessness and low vacancy rates in the private rental market.
- Over the five years to 2013, the overall gap is projected to grow to 203,000 dwellings (based on assumptions of medium growth in supply and underlying demand).
- By 2028 the same projection assumptions produce a cumulative gap of 431,000 dwellings.
- These estimates are highly sensitive to assumptions used.
The long-term estimates are unlikely to be realised because, in most conceivable circumstances, a large cumulative gap would cause compensating adjustments in price, and in levels of production and demand that would fully or partially mitigate that deficit.
The obvious exception is in the social housing sector, where a looming gap might bring on some private investment at the margin, but the main response would need to lie with government policy and expenditure.
While the Australian Government has announced policies and program responses to address homelessness and increase construction of both new social housing dwellings and private rental accommodation, these actions will take time to work effectively and will require significant additional capital and recurrent expenditure to address the full extent of the deficit at the lower end of the housing market.
Overview
This chapter examines the apparent gap between housing demand and supply from two perspectives:
- What is the gap between total demand and total supply in 2008
- How the gap may change over time as demand and supply change.
The gap between total demand and total supply in 2008
There are a number of possible indicators of the present gap between supply and demand. In estimating this gap as at June 2008, the Council has selected:
- the number of homeless households sleeping rough
- the number of homeless households sharing accommodation with friends or relatives
- the number of marginal residents of caravan parks45
- the difference between the present rental vacancy rate and that required to ‘clear’ the normal volume of new letting transactions.
Limitations in the availability and quality of data in these and other gap-related areas will be addressed to improve calculations in future reports.
Homeless persons – sleeping rough
The ABS estimates there were 104,700 homeless persons on Census night 2006, of whom 16,400 were ‘sleeping rough’ (Table 4.1). People who are part of the ‘primary homelessness’, or ‘sleeping rough’ group, include those without conventional accommodation – living on the streets and sleeping under bridges or in places like deserted buildings, improvised dwellings or parks. These 16,400 persons represented 8,800 households including 5,500 single person households, 1,400 couples without children and 1,700 families with children.46
| State/ territory |
NSW | Vic. | Qld | SA | WA | Tas. | NT | ACT | Aust. |
|---|---|---|---|---|---|---|---|---|---|
| Homeless persons |
3,600 | 2,300 | 5,100 | 900 | 2,400 | 400 | 1,800 | 100 | 16,400 |
Source: C Chamberlain & D MacKenzie, Counting the homeless 2006, Tables 6.3, 6.6 and 6.8, cat. no. 2050.0, Australian Bureau of Statistics, Canberra, 2008.
To meet the needs of rough-sleeping households, it is assumed that an additional 8,800 dwellings would have been needed in 2006.
Homeless persons have a diverse range of housing needs and often require other support services. More analysis is needed to establish the most appropriate quantity and type of housing supply responses required to reduce homelessness.
Homeless persons – sharing with friends or relatives
Persons sharing accommodation with friends or relatives are counted as being homeless if they are residing temporarily with other households because they have no accommodation of their own. This group forms part of the ABS classification of secondary homelessness.
In 2006, the ABS identified 47,300 persons (35,000 households) in the homeless population sharing accommodation with friends or relatives (Table 4.2).
Source: C Chamberlain & D MacKenzie, Counting the homeless 2006, cat. no. 2050.0, Tables 6.3, 6.6 and 6.8, Australian Bureau of Statistics, Canberra, 2008.
Homeless persons – marginal residents of caravan parks
The ABS defines marginal residents of caravan parks as people who are renting a caravan at their usual address, with no-one in the dwelling having full-time work of 35 hours or more.47 The 2006 Census identified 17,500 marginal residents of caravan parks (Table 4.3), noting that this figure had declined from 22,800 persons in 2001. These 17,500 residents comprised 12,500 households.
Source: C Chamberlain & D MacKenzie, Counting the homeless 2006, Table 8, cat. no. 2050.0, Australian Bureau of Statistics, Canberra, 2008.
Government initiatives in the White Paper on Homelessness
In December 2008, the Australian Government launched its White Paper on homelessness, The Road Home: A National Approach to Reducing Homelessness.48 The White Paper foreshadowed an additional $1.2 billion over four years in new funds to help homeless Australians. It included specific goals to halve overall homelessness by 2020, and to provide support and accommodation to all rough sleepers. While the Council acknowledges the initiatives in the White Paper, for the purpose of assessing the total gap between housing demand and supply, the 2006 figures for homelessness identified above have been used as a component of the gap between housing demand and supply in this report over the full 20-year period of the projections. This approach will be reviewed in the Council’s future reports.
Efficient vacancy rate in housing submarkets
The equilibrium vacancy rate for the private rental market is generally acknowledged to be 3 per cent of stock. In relation to private rental, current vacancy rates vary across Australia and only those for capital cities are published regularly.
Table 4.4 provides an estimate of the number of additional vacant dwellings that would be required in the private rental market to reach 3 per cent vacancy in 2008. The capital city vacancy rate is assumed to approximate that for each respective State and Territory. The Council estimates that an additional 26,000 vacant private rental dwellings, mainly in New South Wales and Victoria, would be required in 2008.
Notes:
(a) Source: Real Estate Institute of Australia; vacancy rates for capital cities are applied to States and Territories.
(b) Source: Australian Bureau of Statistics; numbers may not sum to Australian total due to rounding.
(c) Source: NHSC estimate.
(d) Estimate is less than 500 and is rounded to zero.
Source: Australian Bureau of Statistics, Survey of Income and Housing: CURF on CD-ROM/RADL, 2005–06 (Second Edition), cat. no. 6541.0.30.001, ABS, Canberra, 2008; Real Estate Institute of Australia, Real Estate Market Facts, June Quarter 2008, REIA, Canberra, 2008; NHSC estimates based on McDonald–Temple medium household growth scenario.
The size of the gap in 2008
Table 4.5 summarises the previous sections and shows that in 2008 the estimated size of the gap between demand and supply was a shortfall of 85,000 dwellings.
Table 4.5: Estimated dwelling gap, Australia, June 2008 (rounded to nearest '000)

An important exclusion from these calculations is an allowance for the number of people who are living in non-private fixed dwellings such as rooming houses, hotels, motels and institutions and have no other residence. Further research is needed to determine what proportion of this group should be included in the demand–supply gap.
A further issue relates to the role that unoccupied dwellings play in relation to gap pressures. The 2006 Census found that there were 830,000 vacant dwellings (9.85 per cent of total stock) see Table 4.6. There is little information available on the utilisation of these vacant dwellings. Specific purposes include vacant stock awaiting sale, demolition or replacement, and holiday homes.
The number of unoccupied dwellings at the 2006 Census had increased significantly from the 718,000 unoccupied dwellings (9.22 per cent of total stock) in 2001. The comparable figure for the 1996 Census was 679,000 unoccupied dwellings, making up 9.47 per cent of the stock. In 1991, there were 598,000 unoccupied dwellings representing 9.26 per cent of the stock (see Appendix 2, Table A4.2).
The proportion of unoccupied dwellings in 2006 also varied significantly between different parts of Australia – for example, the proportion was 4.95 per cent in outer western Sydney and 11.2 per cent for the Gold Coast, supporting the assumption that a large proportion of vacant dwellings are holiday homes. The Council will undertake further research in relation to unoccupied dwellings prior to its next report.
Source: Australian Bureau of Statistics, 2006 Census tables, Australia, ‘Dwelling Structure by Occupied/Unoccupied Dwellings’, cat. no. 2068.0, ABS, Canberra, 2007.
There are other aspects of housing need that could be considered for inclusion in the definition of the demand–supply gap. One such aspect is overcrowding. The 2006 ABS Survey of Income and Housing identified that 2.8 per cent of Australian households in 2005–06 were overcrowded using the Canadian National Occupancy Standard.49 Applying updated population projections and assuming this distribution is the same, it is estimated there would be 234,000 overcrowded households in 2008. This includes 42,000 households where two or more bedrooms are needed to avoid overcrowding. Conversely, as shown in Table 4.7, 10 per cent of households occupy dwellings where there are three or more spare bedrooms. Given that overcrowding relates to the number of bedrooms for specific families and the way in which existing stock is utilised (rather than being an issue of overall dwelling numbers), the Council has not included an allowance for overcrowded households in its demand–supply gap estimates.
Note: dwelling utilisation is determined using Canadian National Occupancy Standard. Numbers may not sum to totals due to rounding.
Source: derived from Australian Bureau of Statistics, Housing Occupancy and Costs, Australia, 2005–06, Table 14, cat. no. 4130.0.55.001, ABS, Canberra, 2007 and 2008 Council estimates.
Future changes in the demand–supply gap
Estimating the future balance between housing demand and supply is a perilous undertaking because supply and demand influence each other and the emergence of a significant imbalance is likely to stimulate a market response. This dynamic aspect of the market should be borne in mind when interpreting the following projections.
A further hazard in projecting the gap is the prospect of change in economic circumstances and government policies and programs affecting the housing market and homelessness. It is axiomatic that economic cycles, policies and programs will change at some point over the 20-year forecasting period; indeed, we are seeing all three at present.
The following projections of the demand–supply gap are derived simply by subtracting the supply projections (Chapter 3) from the demand projections (Chapter 2) taking into account the estimated gap of 85,000 as at June 2008. The 'central' estimate of the gap presented in Table 4.8 compares the medium growth projection of demand with the medium growth projection for supply (i.e. average new dwelling production trend since 1980 adjusted for demolitions).
The value of these projections is simply their capacity to show how the gap between supply and demand would develop in a situation of ‘all other things being equal’. This provides a potential springboard for change on the part of housing providers and government policy and programs. Publicity about declining relative supply and deteriorating affordability might have some impact on consumers’ aspirations for ownership of larger dwellings.
Medium demand and medium supply
Table 4.8 shows how, under medium supply and medium demand assumptions, the estimated gap of 85,000 in 2008 will change over the next 20 years. Over the two years to 2010, the gap grows by an estimated 46,000 dwellings to be 131,000 dwellings. This is the result of an estimated 259,000 net new dwellings over the period while underlying demand increases by 305,000 households.
After five years, by 2013, the gap grows by an estimated additional 118,000 dwellings to be 203,000 dwellings. By 2018, the gap has increased to 316,000 dwellings and, by 2028, it is 431,000.
Source: NHSC estimates based on McDonald–Temple medium household growth scenario; NHSC estimates based on trends in dwelling completions; see Appendix 2 and Appendix 3 for full details.
Sensitivity of estimates of the gap
These projections are sensitive to the assumptions used. This is illustrated by Table 4.9, which shows underlying demand and dwelling production increases over the five years from 2008 to 2013, and the resultant gap, using different combinations of the three underlying demand scenarios and the three dwelling production scenarios.
For example, the projections of high demand growth and high growth in supply indicate growth in demand over the five-year period of 871,000 additional households and additional supply of 781,000 dwellings, with a gap between the two of 90,000 dwellings. This compares with the low demand and medium supply projection, which indicates for the same period an increase in demand of 698,000 while supply grows by 653,000, leaving a gap of 45,000.
(a) Size of gap is measured as the difference in the increase in demand over the increase in supply. A negative value indicates oversupply.
Source: NHSC estimates based on McDonald–Temple low, medium and high household growth scenarios; NHSC estimates based on trends in dwelling completions; see Appendix 2 and Appendix 3 for full details.
The data in Table 4.9 exclude the estimated ‘initial gap’ in 2008 (relating to homelessness and private rental vacancy rates). The effect of including this initial gap is shown in Table 4.10, which shows the change in the total gap over the five years 2008 to 2013, using different combinations of the three underlying demand scenarios and the three dwelling production scenarios. For example, a high growth in demand and also supply projection as discussed above would see the overall gap in demand grow from 85,000 dwellings to 175,000 dwellings over the five-year period. This compares with a low demand and medium supply projection, which estimates for the same period an increase in the gap from 85,000 to 130,000.
(a) A negative value indicates oversupply.
Source: NHSC estimates based on McDonald–Temple low, medium and high household growth scenarios; NHSC estimates based on trends in dwelling completions; see Appendix 2 and Appendix 3 for full details.
Tables 4.11 and 4.12 present the same approach as that used in Tables 4.9 and 4.10 but refer to the 20-year rather than the five-year projection period.
Table 4.11 shows, for instance, that high growth projections for demand and supply indicate a growth in demand of 3,489,000 additional households by 2028 and supply growth of 3,246,000 dwellings over this period, with a gap between the two of 243,000 dwellings. This compares with the low demand and medium supply projections, which leave a gap of 185,000.
(a) Size of gap is measured as the difference in the increase in demand over the increase in supply. A negative value indicates oversupply.
Note: There are minor variations in the low and medium supply projections compared with those given elsewhere in this report due to rounding.
Source: NHSC estimates based on McDonald–Temple low, medium and high household growth scenarios; NHSC estimates based on trends in dwelling completions; see Appendix 2 and Appendix 3 for full details.
The data presented in Table 4.12 include the initial gap relating to homelessness and rental vacancy rates. High growth in demand and supply as discussed above would see the overall gap in demand grow from 85,000 dwellings to 328,000 dwellings over the 20-year period. This compares with a low demand and medium supply projection, which would increase the gap from 85,000 to 270,000.
(a) A negative value indicates oversupply.
Source: NHSC estimates based on McDonald–Temple low, medium and high household growth scenarios; NHSC estimates based on trends in dwelling completions; see Appendix 2 and Appendix 3 for full details.
Other considerations
As discussed above, the projections presented in this chapter are simplistic in the sense that they do not incorporate the interaction of changes in building activity or population growth with factors that underlie the overall level of economic activity.
The projections are based on past trends and thus on past economic activity. Being based in each case on an effective constant level of economic activity and household growth, the projections do not incorporate fluctuations in activity associated with economic cycles. It was observed in Chapter 2 that the medium projection of supply growth could be optimistic in the shorter term in the light of present economic conditions. If this is so, and household growth continues apace, there is a prospect of a wider gap between demand and supply over the next three to five years.
Looming skills shortages in the construction sector threaten to widen the gap over a longer period.
The impact of current or future government policy initiatives responding to housing need have not been factored into the calculations. Apart from other considerations, their impact is difficult to assess at this stage. If effective, the Australian Government’s broad-based responses to homelessness and housing affordability should reduce the demand–supply gap. Related State and Territory policy and program responses should also contribute. Again, however, it is too early to assess whether these responses will have a minor or major impact, whether due to funding levels, the appropriateness of program settings, or market reaction to them.
As noted in several places in the report, a more sophisticated approach to projecting demand, supply and the gap between them would be based on modelling the variety of economic factors influencing the balance between housing supply and demand. The development of such modelling capacity will be considered by the Council for future reports.
Key indicators for demand–supply gap
The Council intends to monitor the change in the demand–supply balance and the supply of housing that is affordable to low income households as part of its annual reporting. The Council will undertake further work relating to the baseline for monitoring and reporting in subsequent annual reports.
Two initial measures of the demand and supply balance proposed by the Council are:
- the cumulative difference between annual growth in aggregate demand and supply
- the adequacy of annual construction activity.
Key Indicator 1 – Cumulative difference between aggregate demand and supply
Key Indicator 1 measures the cumulative difference between growth in aggregate demand and supply by calculating the net number of additional dwelling units since base year less the number of additional households since base year.
Growth in aggregate demand is the effective number of additional households since base year as measured by the ABS.
The difference between current year and base year aggregate demand household projections approximates the difference between two point in time measures – one at 30 June of the current year and the other as at 30 June of the base year.
Growth in aggregate supply is the net number of additional units since base year and is measured using the ABS dwelling completions data adjusted using Council estimates of demolitions for the financial years ending 30 June for the years since the base year.
As 2008 is the base year, Key Indicator 1 comprises only the initial gap of 85,000 dwelling units. Derivation of this figure is explained in Table 4.5.
| Whole of Australia | Capital cities | Balance of State | |
|---|---|---|---|
| Initial supply gap indicated by homelessness and rental vacancy rates |
85,000 | n.a. | n.a. |
| Cumulative difference between aggregate demand and supply |
85,000 | n.a. | n.a. |
Source: NHSC estimates of initial gap due to homelessness and inadequate vacancy rates.
Key Indicator 2 – Adequacy of annual construction activity
The adequacy of annual construction activity is measured by the net number of additional units in the last year less net number of additional households in the same year.
Net number of additional units in the last year is measured using the ABS dwelling completions data adjusted using Council estimates of demolitions for the financial year ending 30 June 2008.
Net number of additional households in the last year is the projected annual growth in household numbers using the medium household demand projection for 2008. The difference between 2007 and 2008 household projections approximates the difference between two point-in-time measures – one as at 30 June 2007 and the other as at 30 June 2008.
Using this methodology for the whole of Australia, the cumulative difference in 2007–08 is a supply shortfall of 20,000 – based on additional supply of 129,000 units less number of additional households of 149,000 in 2007–08.
| Whole of Australia | Capital cities (a) | Balance of state (b) | |
|---|---|---|---|
| Additional supply in last year |
129,000 | 74,000 | 55,000 |
| Number of additional households in last year |
149,000 | 85,000 | 64,000 |
| Adequacy of annual construction activity |
–20,000 | –11,000 | –9,000 |
(a) Sydney, Melbourne, Brisbane, Adelaide and Perth only.
(b) Includes Hobart, Darwin and Canberra.
Notes:
Negative numbers in the indicator imply a supply shortfall.
It could be assumed that the 20,000 shortfall for Australia as a whole in 2007–08, when linked to the estimated gap at June 2008 could imply a gap of 65,000 as at June 2007. It needs to be noted that these figures are subject to the qualifications outlined elsewhere in this report.
Source: NHSC estimates based on McDonald–Temple low, medium and high household growth scenarios; NHSC estimates based on trends in dwelling completions; see Appendix 2 and Appendix 3 for full details.
45. The ABS defines marginal residents of caravan parks as people who are renting a caravan at their usual address, with no-one in the dwelling having full-time work of 35 hours or more (C Chamberlain & D MacKenzie, Counting the homeless 2001, cat. no. 2050.0, Chapter 7, Australian Bureau of Statistics, Canberra, 2003).
46. See Appendix 2, Table A4.1: Estimated dwelling need of rough sleepers, 2006.
47. C Chamberlain & D MacKenzie, Counting the homeless 2001, cat. no. 2050.0, Chapter 7, Australian Bureau of Statistics, Canberra, 2003.
48. Australian Government, The Road Home – A National Approach to Reducing Homelessness, FaHCSIA, Canberra, December 2008.
49. Australian Bureau of Statistics, Housing Occupancy and Costs, Australia, 2005–06, Table 14, cat. no. 4130.0.55.001, ABS, Canberra, 2007.