Do you know some real estate agents are intentionally gaming the MLS by relisting houses after they stay in the market for too long?

Call them determined or call them unscrupulous, agents are relisting houses that haven't drawn buyers, leading other agents to believe that the houses are newly listed. This practice came to light when an alert pro in California was surprised to see the average days on the market decreasing in some multiple listing services. The sleuth, Mike Lyon, president of TrendGraphix, a data miner and producer of software for the real estate industry in Sacramento, Cal., detected relistings in high-priced East Coast and West Coast markets, but he would not disclose the names of specific metropolitan areas.

His discovery makes days on the market a questionable indicator for buyers. A better measure of a local housing market is "months' supply," or how long the current inventory will last given the current pace of sales. Between June 2005 and June 2006, months' supply increased nationally from 4.4 months to 6.8 months, according to the National Association of Realtors, so there are a lot of homes for sale in most communities. You can ask the agent for a "listing history" on any house.