Federal Reserve Chairman Alan Greenspan first addressed the question of a housing bubble in testimony before the Joint Economic Committee on April 17, 2002. He dismissed the idea--or, for that matter, any comparison to the stock market, which had recently gone through a high-tech bubble--on the grounds that housing was different because of substantial transaction costs and more limited opportunities for speculation.
Greenspan also argued that there really wasn't a single national market for housing, but rather a collection of many local markets. Even if a bubble emerged in one market, he said, there was no reason to think it would spill over into other markets.
In June 2002, I filed a report by economist Ed Leamer of UCLA noting that the ratio of home prices to rent was rising rapidly and that this represented a kind of price to earnings ratio for the housing market.
Like the stock market's P/E ratio, when it rises rapidly above historical norms in a short period of time, it's is a good sign that there is a bubble--and that it could burst quickly.
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