Price errors
Errors in sales prices are one of the issues Investopedia pointed out in its look at Zillow’s Zestimates.
“Zillow factors the date and price of the last sale into its estimate, and in some areas, these data make up a big part of the figure. If this information is inaccurate, it can throw off the Zestimate,” they said. “And since comparable sales also affect a home’s Zestimate, a mistake in one home’s sales price record can affect the Zestimates of other homes in the area. The Zestimate also takes into account actual property taxes paid, exceptions to tax assessments and other publicly available property tax data. Tax assessor’s property values can be inaccurate, though. The tax assessor’s database might have a mistake related to a property’s basic information, causing the assessed value to be too high or too low.”
In June, Zillow’s much-maligned (by industry experts, anyway) Zestimates got an upgrade with a new algorithm. Zillow CEO Spencer Rascoff has famously called his company’s price estimates, “a good starting point” and copped to a median error rate of approximately 8%. With their new algorithm, they say it’s dropped to 6.1%.