Globe Staff

The median price for Massachusetts single-family homes sold in January rose 9.6 percent to $285,000 from $260,000 in January 2009, the second consecutive month that median prices for single-family homes increased by about 10 percent on a year-to-year comparison basis, the Warren Group reported today.

On a volume basis, the number of Massachusetts single-family homes rose 11.8 percent to 2,153 from 1,926 in January 2009; that was the fourth consecutive month of double-digit percentage increases, said the Warren Group, a Boston firm that tracks the local housing market and publishes Banker & Tradesman.

"The gains in both sales volume and median prices are a vast improvement to the housing market�s slow start last year," Warren Group chief executive Timothy M. Warren Jr. said in a statement. "The improving economic picture and incentives like the home-buyer tax credit and low mortgage interest rates have aided the housing market. Still, it�s important to keep in mind that last month�s median selling price is 12 percent lower than it was in January 2008."

Despite last month's showing, there are some concerns. Recent momentum in the housing market has been propelled by a temporary tax credit for home buyers and mortgage rates near historic lows. That tax credit is scheduled to expire later this year, and mortgage rates are likely to rise, causing the loss of some momentum. Meanwhile, home owners who don't need to move are reluctant to put their properties up for sale, thinking they may be able to get a better price if they wait. That reluctance has led to an inventory shortage, analysts said.