Barclays Capital says house prices may fall by about 15% over the next two years, hitting their long-term trend levels next year, then overshooting on the downside for another year.

If the trend is up, mark all downside penetrations during the look-back period, add their depths, and divide the sum by the number of penetrations.

And Fed officials seem well aware of the downside risks to trend and potential growth, so the mistakes of the 1970s seem unlikely to be repeated.