The group's chief economist, Lawrence Yun, attributed the discrepancy to divergence that developed over time between sales reported by multiple listing services throughout the country and those determined by a Census Bureau benchmark.
About half the revision is the "result solely from a decline in for-sale-by-owners, with more sellers turning to real estate agents when the market softened," Yun said.
Some listings appeared on more than one multiple listing service, he said, adding that "issues related to house-flipping also contributed to the downward revisions."
"From a consumer's perspective, only the local market information matters, and there are no changes to local multiple-listing-service data or local supply-and-demand balance, or to local home prices," Yun said.
Prudential Fox & Roach senior vice president Steve Storti said data used to compile its monthly HomExpert Market Report for the eight-county Philadelphia region are "as accurate as the input directly into the multiple listing service from the brokers in the market."
"There is no chance of mass inaccuracy with this kind of direct analysis, in which you can drill down to the individual transactions that make up a data point," Storti said. (Figures supplied by HomExpert formed the basis of The Inquirer's Home Price Survey in October.)
The Realtors' national data are based on estimates of all preowned-home sales, even when real estate agents are not involved. HomExpert limits data to brokers' transactions and uses exact numbers, not estimates.
For November, HomExpert reported sales in the eight-county region totaling 3,118, 9.8 percent higher than the 2,800 sold in the same month in 2010. There were 3,022 sales in October, an increase of about 3 percent month to month, HomExpert said.
