Professor Robert Shiller has leveraged his repeat sales index by developing a new monthly national housing market report with Standard & Poor called S&P/Case-ShillerÂ® Home Price Indices. I find that repeat sales indexes can be very inaccurate and lag the market because they don’t reflect changes in the houses being measured for multiple sales, the data set is too thin, and the response to sudden changes in a market is delayed. This particular report addresses composites of 10 and 20 metro areas so its not really a national housing market indicator since metro areas are distinctly different markets than outlying areas. However, the index seems to address one of their biggest flaws:
Their purpose is to measure the average change in home prices in a particular geographic market. They are calculated monthly and cover 20 major metropolitan areas (Metropolitan Statistical Areas or MSAs), which are also aggregated to form two composites – one comprising 10 of the metro areas, the other comprising all 20. The indices measure changes in housing market prices given a constant level of quality. Changes in the types and sizes of houses or changes in the physical characteristics of houses are specifically excluded from the calculations to avoid incorrectly affecting the index value.
“The annual declines in the composites are a good indicator of the dire state of the U.S. residential real estate market,” says Robert J. Shiller, Chief Economist at MacroMarkets LLC. “ The 10-City and 20-city Composites are both showing negative annual returns, a striking difference from the 15.1% and 14.7% returns they reported this time last year. The dismal growth in the 10-City composite is now at rates not seen since January 1994.”
Its the first time in 11 years that home prices go negative. A possible theory for the weakness is relating to the interplay between new home sales and existing home sales. I am not sure I buy into it but its interesting to consider nevertheless.
The lag in timing on this index is really showing the markets around the November 2006 election since the study is based on January 2007 closings. At -0.2% and -0.7% for the 10 and 20 city composite, its is a significant drop from the 15% annual appreciation rates seen a year earlier but not unexpected.
I know economists are paid to worry, and I am not cheerleading here, but does Professor Shiller have to use the word dire in his description?