Seattle’s Zillow.com, the online company known for publishing the estimated values of millions of homes, launched a reworked version of its Web site today. Information that updates a home’s stats, such as number of bedrooms, and that are provided by homeowners or real estate agents now will count toward the calculation of what the company calls Zestimates. And, in turn, applying such feedback should improve the accuracy of the Zestimates, according to Spencer Rascoff, Zillow’s vice president of marketing.

Homeowners could add such information starting about a year ago. But Rascoff said it took awhile to gather enough data to make sure such additions would help, not hurt, the Zestimates.

Also, models used to calculate a home’s estimated value now will evaluate a home on a neighborhood level rather than comparing it to homes countywide, Rascoff said. Zillow, for example, has broken Tacoma into eight neighborhoods.

All of which is expected to bring Zestimates closer to the price a home is eventually sold for – the measure used by the company to determine accuracy. The accuracy of Zestimates in the Seattle-Tacoma area is expected to improve by 7 percent, Rascoff said. (That compares to 12 percent nationwide. The improvement here is smaller, Rascoff said, because local Zestimates were already more accurate than elsewhere.) Using Zillow's new modeling, 86 percent of Zestimates in the Seattle-Tacoma area should be within 20 percent of an eventual sale price.

At least one Central Tacoma property saw a new and improved Zestimate this morning. A co-worker whose spouse closely follows their home at Zillow said their house’s Zestimate increased by about 50 percent, presumably because the site previously hadn’t accounted for the home’s full square footage.