Data Coverage and Zestimate® Accuracy

The home data we have compiled to generate a Zestimate home valuation varies by location. Some counties provide all the data we could hope for, but others are lacking such key things as the number of bedrooms and bathrooms, or, in some cases, the square footage of the home. The more data we have, the more accurate the Zestimate. And, we've made it easier for our users to help us improve accuracy by incorporating edited home facts into our Zestimate calculations. In some areas, we might not be able to produce a Zestimate at all, but we do have some basic information on the homes. The tables below show you where we have Zestimates and other home information.

To measure the accuracy of the Zestimates, we've gone back in time and compared the historic Zestimates with the actual transaction prices of homes that sold. The tables below also provide various measures of that accuracy.

What's a Zestimate?

A Zestimate home valuation is Zillow's estimated market value. It is not an appraisal. Use it as a starting point to determine a home's value. Learn more.

  • West Virginia Counties

West Virginia

County Zestimate Accuracy % Homes on Zillow % Homes With Zestimates Within 5% of Sale price Within 10% of Sale Price Within 20% of Sale Price Median Error
Barbour 99% 0% -- -- -- --
Berkeley 99% 0% -- -- -- --
Boone 99% 0% -- -- -- --
Braxton 99% 0% -- -- -- --
Brooke 99% 0% -- -- -- --
Cabell 99% 99% 5% 8% 19% 59.9%
Calhoun 99% 0% -- -- -- --
Clay 99% 0% -- -- -- --
Doddridge 99% 0% -- -- -- --
Fayette 99% 89% 4% 4% 10% 101.3%
Gilmer 99% 0% -- -- -- --
Grant 99% 0% -- -- -- --
Greenbrier 99% 0% -- -- -- --
Hampshire 99% 0% -- -- -- --
Hancock 99% 0% -- -- -- --
Hardy 99% 0% -- -- -- --
Harrison 99% 0% -- -- -- --
Jackson 99% 0% -- -- -- --
Jefferson 99% 0% -- -- -- --
Kanawha 99% 99% 19% 41% 65% 13.7%
Lewis 99% 0% -- -- -- --
Lincoln 99% 0% -- -- -- --
Logan 99% 0% -- -- -- --
McDowell 99% 0% -- -- -- --
Marion 99% 0% -- -- -- --
Marshall 99% 0% -- -- -- --
Mason 99% 0% -- -- -- --
Mercer 99% 0% -- -- -- --
Mineral 99% 0% -- -- -- --
Mingo 99% 0% -- -- -- --
Monongalia 99% 0% -- -- -- --
Monroe 99% 0% -- -- -- --
Morgan 99% 0% -- -- -- --
Nicholas 99% 0% -- -- -- --
Ohio 99% 0% -- -- -- --
Pendleton 99% 0% -- -- -- --
Pleasants 99% 0% -- -- -- --
Pocahontas 99% 0% -- -- -- --
Preston 99% 0% -- -- -- --
Putnam 99% 99% 7% 11% 22% 49.6%
Raleigh 99% 0% -- -- -- --
Randolph 99% 0% -- -- -- --
Ritchie 99% 0% -- -- -- --
Roane 99% 0% -- -- -- --
Summers 99% 0% -- -- -- --
Taylor 99% 0% -- -- -- --
Tucker 99% 0% -- -- -- --
Tyler 99% 0% -- -- -- --
Upshur 99% 0% -- -- -- --
Wayne 99% 0% -- -- -- --
Webster 99% 0% -- -- -- --
Wetzel 99% 0% -- -- -- --
Wirt 99% 0% -- -- -- --
Wood 99% 0% -- -- -- --
Wyoming 99% 0% -- -- -- --

Last updated: June 4, 2008
Note: Zestimate accuracy is computed by comparing the final sale price to the Zestimate on or before the sale date. The data herein is computed for the three-month period ending Dec. 31, 2007.

Click here to download an Excel spreadsheet of this data.

Definitions

Zestimate Accuracy/Star Rating:
This rating is tied to the Median Error in an area.
The ratings are as follows:
  • Four Stars = Best Zestimate
  • Three Stars = Good Zestimate
  • Two Stars = Fair Zestimate
  • One Star = Tax assessor's value, or unable to compute Zestimate accuracy
  • 0 stars = No valuation
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Tax Assessor's Value

Depending on the jurisdiction where you live, this value could be the tax assessed, tax appraised, or market assessed value. This value comes from the taxing authority of the city, county or state where you live; this is not Zillow's value.

Note: Tax assessor's values differ from Zillow's Zestimate, which is computed by entering numerous data points into a proprietary formula, often resulting in a more accurate value estimate.

Homes on Zillow:
This indicates the percentage of homes for which we have data (e.g., number of bedrooms or bathrooms) in a particular locale. These are the homes you can find via maps or search on Zillow.com.
Homes With Zestimates:
We can only calculate Zestimates for homes where we have certain data, including transactions. This column indicates the percentage of homes in an area with Zestimates.
Within 5% of Sale Price:
This is the percentage of transactions in a location for which the Zestimate was within 5% of the transaction price. For example, in the Portland area, 35% of the time the Zestimate was within 5% of the selling price.
Within 10% of Sale Price:
This is the percentage of transactions in a location for which the Zestimate was within 10% of the transaction price.
Within 20% of Sale Price:
This is the percentage of transactions in a location for which the Zestimate was within 20% of the transaction price.
Median Error:
Half of the Zestimates in an area were closer than the error percentage and half were farther off. For example, in Seattle, Zestimates for half of the homes are within 7.5% of the selling price, and half are off by more than 7.5%.
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