UTSA College of Business faculty members study Zillow home estimates

Home Value

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(March 22, 2010)--Are estimates of home values at Zillow.com accurate? A research study conducted by University of Texas at San Antonio business faculty members Daniel Hollas, Ron Rutherford and Tom Thomson found that Zillow's market value estimates are not any more reliable than owners' estimates of value.

Their study, "Zillow's Estimates of Single-Family Housing Values," examined how Zillow's estimates of value, known as Zestimates, compares to actual sales prices. Zillow.com is a Web site that provides estimated market values for houses. The research was published in The Appraisal Journal's Winter 2010 issue.

The faculty members looked at 2,045 single-family home sales in Arlington, Texas, which was rated by Zillow as having the most accurate data. The study found that 40 percent of the homes in the sample were overvalued by Zillow by more than 10 percent, compared to actual sales prices.

"Given these results, homeowners can make good use of Zillow's Zestimates, but in most cases Zillow should not be relied on to provide an accurate estimate of value," said Ron Rutherford, the Elmo J. Burke Jr. Endowed Chair in Building Development. "It appears, based on results from prior research and the current results, that homeowners are able to determine the value of their own homes better than an automated system such as Zillow."