Monday, August 31, 2009

UPDATE 2 - A chronic housing shortage: Myth or reality?

This is my final post on the housing shortage debate. After a little probing, I have isolated the single point that leads astray the data rich, but theory poor, residential property analysts. It is this. Housing shortage proponents believe that housing supply is not very responsive to price changes, or the jargon, supply in inelastic. As such, we can expect another house price spike as we wait for supply to catch up with expanding future housing demands.

I would like to think that today’s ABS release of building approvals data confirms my point, and makes a mockery of housing shortage predictions, such as those of Paul Braddick of ANZ. Braddick seems to acknowledge the housing shortage as some kind of inside joke when he writes:
If housing supply remains on its current trajectory, Australia will face a critical, and potentially intractable shortage of housing throughout the decade ahead that would force rents and house prices significantly higher and drive both rental and house purchase affordability/availability to extremely difficult levels. (my emphasis)
To look at the graph below, and make dire predictions based in extrapolating a one year trend in supply, in light of historical evidence, is probably one reason for the poor reputation of economists.

By the way, Braddick has claimed a shortage for some years, and in 2007 stated that buying a home was going to get much harder, and that we face supply constraints. Yet in the year following these claims prices dropped and affordability increased. I thought houses were like bananas. A supply constraint causes prices to rise, not fall. But if you make the same prediction for long enough it is bound to be right eventually.

Where is the theory in all these extrapolative forecasts? In Joye’s own words, his solution is to ‘elastify supply’, but how elastic is supply currently? And is there a problem with too much elasticity, which may accentuate the boom and bust cycle? Let’s not also forget the fact that supply is normally more elastic in the long run than in the short run anyway.

Why do we not see these types of conclusions from our top economists instead?
…the projections of demand, of supply and of the gap between them are simplistic and unlikely to be realised in the longer term. The housing market is dynamic, as is the economy as a whole, and the emergence of a major gap between effective demand and supply would stimulate market reactions affecting price (affordability) and aggregate supply.
There are my last thoughts before putting this debate to rest.

  • Housing demand comprises rental and owner-occupier demand. Investor demand is simply a function of rental demand (income) and growth expectations, which may be partly driven by owner-occupier demand.
  • The elasticity of supply of housing appears quite reasonable, but I have yet to find a good recent estimate for Australian housing. Even Joye and Co’s epic volume on home ownership, with a chapter on the elasticity of housing supply, fails to estimate the elasticity figure itself, and whether there has been some recent decline attributable to regulatory changes. In the UK it, the elasticity of supply of housing appears to be between 1 and 3. My own back of the envelope estimates using ABS weighted homes average price for capital cities (price), and dwelling units completed (quantity) result in a similar range of estimates (depending on whether monthly, yearly, or lagged).
  • Although a Robertson/Keen type wager does not interest me so much, I am still prepared to offer a forecast. The growth in dwelling prices from July 2009 to July 2011 will be less than the growth in prices from July 2005 to July 2007. I know, it’s not particularly shocking, but it makes my point that the methods used to justify a housing shortage are flawed, and do feed into house prices.

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