Profile picture for valeriebee1

who does the zillow estimate

  • February 27 - US
  • 0Yes

  • Report a Problem

    Please enter a valid email address.

    Content flagged

    We will review this content. Thanks for helping make the site more useful to everyone. To learn more, read Zillow's Good Neighbor Policy.

    We're sorry. This service is temporarily unavailable. Please come back later and try again.

Be a Good Neighbor. Be respectful and on-topic. No spam or self-promotion! See our Good Neighbor Policy.

 
 

Answers (5)

Profile picture for blue screen exile
If you are interested in the team of statisticians that developed the "method", and process of feeding the data and programming code to the cloud, and process of getting the estimates posted to the site for approximately 21 Billion estimates per year, see:
http://www.zillow.com/blog/research/data/

If you are interested in the patent they wrote and hold on their "method", see:
US Patent #8,140,421

It is a non-linear neural network learning model method of multiple variable for sparse data, similar to the Optical Character Recognition method developed by the U.S. Postal Service with our tax dollars.

Personally, I think they would be better off with an iterative non-linear least squares curve method, but each AVM chooses their own approach and method.

First American Core Logic tried to sue them a number of years ago for patent infringement (Before Core Logic's AVM patent expired)  in order to eliminate their competition and to "steal" details of their method through the "disclosure process", but finally came to a settlement agreement instead.  Core logic offers (for a fee) an AVM product that is the results of 10 different AVM's.  No one AVM method is "best" for all conditions and property types and locations.

Zillow runs separate models for different counties and different property types, and different "missing data".  They occasionally will make a change in a model to a county sufficient to warrant recalculating past estimates to avoid discontinuities based on a "methods change" rather than a "market change".

Zillow publishes a 70% confidence interval with EACH estimate; typically in the magnitude of about +/-10%.  They also public a tolerance range for each county calculated at the end of each fiscal quarter, for how close the "sold" prices came in to the "prior" estimate.

David is complaining about absolutely "nothing" as the changes to the estimates on his home and his neighbor's homes are within the 70% confidence interval, AND the posted tolerance range, and 70% confidence interval implies that the present market value has a 30% chance of being outside that posted range anyway.

The estimates are not intended to benefit house flippers; the estimates will work against flippers ever time, due to the use of prior sales and tax records as part of the estimating method.  The primary purpose of the estimates is to generate local housing indexes similar to Case Shiller.
  • February 27
  • 0Yes

  • Report a Problem

    Please enter a valid email address.

    Content flagged

    We will review this content. Thanks for helping make the site more useful to everyone. To learn more, read Zillow's Good Neighbor Policy.

    We're sorry. This service is temporarily unavailable. Please come back later and try again.

Profile picture for wetdawgs
Zillow's computers (with guidance of a team of statisticians) do the Zestimate.     You can learn more in "what is a Zestimate?"  If you really want to get into the nitty gritty, you can find patents at the US patent website.

Zestimates are starting points. IMHO, the value range is far more important than the one number called a Zestimate. Many people wish that they would include condition and many other factors making them closer to an appraisal, but that isn't possible with computer algorithms using public data.   
  • February 27
  • 0Yes

  • Report a Problem

    Please enter a valid email address.

    Content flagged

    We will review this content. Thanks for helping make the site more useful to everyone. To learn more, read Zillow's Good Neighbor Policy.

    We're sorry. This service is temporarily unavailable. Please come back later and try again.

Profile picture for DavidRosenblum7
Zillow's zestimate are pure fiction. They have devalued our house by almost 26k while every other house in our neighborhood has gone up.

And I can assure you that if you saw the other homes, you would either pick ours or our neighbor's as being the nicest and worth the most money.

Their algorithmns are the pure eyewash.

One day someone's gonna show Zillow damaged them and then the class action suit will follow shortly.
  • February 27
  • 0Yes

  • Report a Problem

    Please enter a valid email address.

    Content flagged

    We will review this content. Thanks for helping make the site more useful to everyone. To learn more, read Zillow's Good Neighbor Policy.

    We're sorry. This service is temporarily unavailable. Please come back later and try again.

Go to the Zillow home page then scroll all the way to the bottom.  Click on the word "Zestimates".  It's pretty much explained there.  It can be updated by an agent's CMA.

Good luck.
  • February 27
  • 0Yes

  • Report a Problem

    Please enter a valid email address.

    Content flagged

    We will review this content. Thanks for helping make the site more useful to everyone. To learn more, read Zillow's Good Neighbor Policy.

    We're sorry. This service is temporarily unavailable. Please come back later and try again.

automated software owned by Zillow which consists of secret proprietary algorithms, Its a fancy way of saying Zillows software takes a bunch or info in from various sources and applies their own calculations to come up with a "Zestimate" on your home. Most likely the coders/computer programers who developed this software had zero Real Estate background, wear big glasses, were under the age of 25 when they coded the program and make millions now like Mark Zukerman. LOL  
  • February 27
  • 0Yes

  • Report a Problem

    Please enter a valid email address.

    Content flagged

    We will review this content. Thanks for helping make the site more useful to everyone. To learn more, read Zillow's Good Neighbor Policy.

    We're sorry. This service is temporarily unavailable. Please come back later and try again.