Profile picture for Tony 88

Zestimate Accuracy a Joke!

I have been following our Zestimate on Zillow for a few years now and I wonder how Zillow can still be in business! Six months ago our house was going up with every new Zestimate change. All our neighbors houses were trending down with every Zestimate change. Now the reverse is happening. All our houses should have a base value based on size and location etc. and all trend with the market - this is not happening with Zillow which makes me very sceptical about the accuracy of the data.
  • January 12 2012 - Lakewood
  • 4
    4Yes

  • 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 (31)

Profile picture for aliciamediaz
Zillow zestimates are a big joke indeed. Areas having poor schools ratings of 7 etc. have higher zestimates than homes in more posh areas. When homes from these posh areas are reviewed, they are selling atleast 50K more than the zestimate. Zillow needs to stop confusing buyers and sellers, alike.
  • December 31 2014
  • 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 aliciamediaz
My friend had a million dollar home, she wanted to sell. A buyer approached her saying, it was zestimated at 700K. My friend showed her a home nearby that had sold for 1.3 million abouts. The buyer  said she could not afford it, but was hoping the zestimate could be right. hehe.
  • December 31 2014
  • 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 user397927
Zestimates are completely inaccurate and no one should rely on them. In Washington State, for example, the Zestimates can be as low as 1/3 lower than ACTUAL government assessments, which are in turn generally considerably lower than actual land values. Zillow is way off, and the company should be embarrassed by its inaccuracy.
  • March 14 2012
  • 2Yes

  • 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 workabee
"The reality here is that zillow is totally inaccurate."

Yeah right Vilyan. If your CMA's are as accurate as the lot sizes on your listings, I'd take Zillow anyday link
  • March 02 2012
  • 3Yes

  • 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
@Vilyan:  what level of accuracy do you offer with your CMAs?  I'd love to see the statistics!
  • March 01 2012
  • 2Yes

  • 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.

ATTENTION SELLERS and BUYERS!!!!


The reality here is that zillow is totally inaccurate. Hire an agent to determain the value of your property. An appraiser would be the best but an agent will give you an idea of where you stand. A GOOD agent that is...SO DONT BELIEVE ANY zestimates online... A realtor and an appraiser will be the most accurate. 
  • March 01 2012
  • 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.

" The Zestimate is costing me customers and costing some family a nice home. I expect Zillow to do a better job fairly valuing land and un-permitted space."

You raise a good point about the land value and the impact on zestimates. I have observed that whilst my county shows land values zillow doesn't and uses the aggregated land and building value. That in itself is misleading as the county uses an "average land value" that ignores some homes are on premium lots to reflect lot size,  outlook and grading. The difference between premium and regular lot values is $50k so by using the aggregate average value zestimates are distorting the value of homes on premium lots. I am sure that this is a regular occurrence that needs attention. 
  • March 01 2012
  • 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 user613294
If it were off by 20%, that might be acceptable, but my property is ten acres in the middle of the Bay Area population center.  The county restricts the listing square footage to 1600 sqft., when the actual is over 4000 sqft. (due to un-permitted buildings that were here when I bought the property).  Zestimate values the ten acres as zero, the un-permitted buildings as zero and compares square footage to square footage with nearby tract houses.

Needless to say, the listing price is 200% of the Zestimate and we've had at least ten potential buyers say, "The property looks worth more, but it's too scary to offer more than the Zestimate."  The Zestimate is costing me customers and costing some family a nice home. I expect Zillow to do a better job fairly valuing land and un-permitted space.  
  • February 25 2012
  • 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 halmonkey
Zestimates from Zillow are worthless and inaccurate, and anyone who follows the real estate market knows there are many valid tools available, and this is not one of them. Zillow would be a much better tool if the Zestimate feature was removed or improved.
  • January 30 2012
  • 2Yes

  • 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 Dunes ..
@Tony

I'd just like to Thank-you for using the Forum and being so civil while Pasa faced the "challenge" of explaining details ect. to people not familiar with such concepts

I'm sure like many others you are truly impressed

Thumbs up for you

  • January 12 2012
  • 3Yes

  • 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 hpvanc
Based on mine and probably Pasadenan's opinion, as well as the recent comment by Whit, the same could be said for agent CMA's when you haven't worked with them on multiple transactions to observe their accuracy, CMA's aren't accurate either.  Would you rather outlaw them or educate consumers to take CMA's with a healthy level of skepticism?  Agents are always holding themselves out to be better experts on valuations than AVM's, Licensed Appraisers, Tax Assessors, owners and buyers, by your logic we need a lot more regulation on agents.
  • January 12 2012
  • 2Yes

  • 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.

 "Fairness" would imply "price fixing", which would violate U.S. anti-trust laws. 

I didn't use the word fairness - I used the phrase 'fair minded'. Most people understand what that means, and Zillows behavior clearly isn't fair minded hence the need to regulate companies that behave so arrogantly when their internal processes and procedures are incapable of providing accurate valuations.
  • January 12 2012
  • 1Yes

  • 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 blue screen exile
"Your choice is not to comment on my question if you find it frustrating!" -

I certainly don't find it at all "frustrating"; I consider it a "challenge" to explain the details and challenges of good modeling to people that are not familiar with such concepts.  It is only in discussing the specifics of the modeling that new innovation will occur to advance the state of the art.
  • January 12 2012
  • 1Yes

  • 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.

I'm a broker and I'll still bet that the Zestimate averages closer to sales price than agent original price.  Just saying.
  • January 12 2012
  • 4Yes

  • 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 blue screen exile
Unfortunately, you would need to learn to be "fair minded" for any argument about "fair mindedness" to make any sense.

Nothing in life was ever promised to be "fair", and certainly not in this country, nor in a "free market economy".  "Fairness" would imply "price fixing", which would violate U.S. anti-trust laws.
  • January 12 2012
  • 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.

 " No one is making you look at this website"

True, but when zillow imposes its unwanted and inaccurate zestimate on a home the owner has no choice but to raise the matter and hope that some fair minded person would accept that the valuation is incorrect and fix it.

 Zillow and fair minded are unfortunately not compatible for whatever reason they choose to be unreasonable. Just as it is equally unreasonable for zillow supporters to be so hostile to anyone who dares to question the accuracy of the holy grail zestimate.
  • January 12 2012
  • 2Yes

  • 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 blue screen exile
"I don't think the buyers of that property felt that Zillow did a good job at minimizing the tolerance range!" -

They don't calculated it on a house by house basis, they calculated it on a county by county basis, using the recent sales compared to the prior Zestimate for the specific sales.

Even gas prices in this area have a tolerance range of a standard deviation of 4.2%, and they widely fluctuate, and don't move at all in unison, even with stations across the street.
  • January 12 2012
  • 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 Tony 88
@ Pasadenan - I'm fully aware that I do not have to look at Zillow and have other options. The purpose of the question was to clarify in my mind a question I have. Given Zillow is unavailable via phone I thought this would be a good avenue.

Your choice is not to comment on my question if you find it frustrating!
  • January 12 2012
  • 3Yes

  • 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 Tony 88
@ hpvan - it actually sold for $650k. I'm not suggesting the sales price should of been nearer the lower end, just that this kind of fluctuation is crazy and confusing to homeowners, buyers and sellers. 

Hopefully the buyer of the property in question, did get a valuation and is happy with the purchase.
  • January 12 2012
  • 2Yes

  • 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 blue screen exile
The most important things in life are not "logical".  Is "love" - logical?

Are the symbols selected for the alphabet "logical"?

Are the phonetics used for reading or writing logical?  Should "read" be pronounced "red" or "reed"?  Can you even necessarily tell by the context?

Most of the other AVM's won't allow you to see a 10 year tend, updated at least monthly, and for extremely good reason... either they don't adjust to market changes, or they fluctuation more than Zillow's.  And they won't publish their tolerance range either, because it it is not that good.

If you don't like what is offered, there are plenty of others.  No one is making you look at this website.  And no AVM ever affected what a willing buyer was willing to pay nor what a willing seller was willing to sell for.  And if Zillow's is used for loan qualifications, Zillow will sue the lender for violating the terms of use.

  • January 12 2012
  • 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 hpvanc
Tony 88,

Was the actual sale price of the sold property you are referencing closer to $550K or $748K?  I'm presuming that you think it is worth something nearer the lower number, I would use that as a start in determining whether the buyer was harmed by the Zestimate.  If a buyer was uninformed enough to believe they were buying instant equity, then . . .
  • January 12 2012
  • 1Yes

  • 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 Tony 88

@ Surbiton - thanks for input. You are right about the curse on unsuspecting property owners!

I have followed another house in the neighborhood that went from $558k to $748k overnight on Zillow. It stayed flat at this level for a year and then dropped overnight back to $548k (where it is today). It was purchased a few months back when it was $748k on Zillow. I know that Zillow is to treated as a gauge, and that professional valuations should be carried out before buying a property, but this kind of fluctuation is ridiculous!

@ Pasadenan - I don't think the buyers of that property felt that Zillow did a good job at minimizing the tolerance range!  
  • January 12 2012
  • 1Yes

  • 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.

"Non-linear learning models are not supposed to make "logical sense"; they are supposed to minimize the tolerance range "

That assumes the source data is correct otherwise garbage in, garbage out. Zillow seems to have so many problems with 3rd party data that seriously impacts the accuracy of the zestimates. With only 5 programmers on staff it takes 8 to 10 months to fix what should be simple problems to correct. 

And Tony88 , unfortunately its not a funny joke but a curse that zillow places on unsuspecting property owners.
  • January 12 2012
  • 2Yes

  • 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 blue screen exile
Non-linear learning models are not supposed to make "logical sense"; they are supposed to minimize the tolerance range.

Independent fluctuations are normal, and are used to help converge on a semi-useful number for use as a "starting point".

There are 1000's of other AVM's, so if you don't like it, you can look elsewhere.  No CMA's publish their tolerance range and many lazy agents do much worse.

Remember, if it did make "logical sense" with simple 3rd grade mathematics, instead of 1000's of AVM's, there would be hundreds of thousands of AVM's, and they would be able to have a narrower tolerance range.  But that isn't going to happen in a free-market economy.  Read the referenced patent again. Then check the price movements daily for each of 20 or so gas stations in the area.
  • January 12 2012
  • 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 Caveat Emptor
Thanks for replies - so they are off 20%, this does not tell me why one house in the same street is going in a different direction to all it's neighbors.

correction, zillow can be off by far more than 20% in any one instance. they are within +/- 20% 80% of the time and wildly wrong 20% or the time. accuracy varies by location and local laws.

as for moving in a different direction, every zestiment is 100% independently calculated(which i admit is weird seeing as how they dont really have very much in terms of ultra specialized data.)

sometimes zillow's base data can be wrong(check your homes sq ft and sale price) but usually thats just zillow being zillow. i think they have some kind of smoothing algorithm that keeps the zestiment from jumping too radically, which means that corrections take a long time and your house/neighborhood gaining value in the last 3 months(if such a thing were possible) may not agree with the direction that zillow is moving your zestiment.
  • January 12 2012
  • 1Yes

  • 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 Tony 88
@ Sunnyview - Thanks for comment. No, the house I'm talking about is owned by me. Purchased in 2002. As I mentioned, when neighbors Zestimates were going down ours was going up. Now neighbors are going up, we are trending down. Makes no logical sense!
  • January 12 2012
  • 3Yes

  • 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 sunnyview
The houses that I have seen that separate from the trend for the neighborhood in my area have often been bought during the highs of the market in 2006-2007.

As the market slows down and the median drops, those houses in my area drop to be closer to the median. I do not know if that applies to the house you are looking at or not, but it might be a possible reason.
  • January 12 2012
  • 1Yes

  • 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 blue screen exile
You are not the only one that has asked that question, and I have not been successful at explaining it to those expecting unison movement yet; but I will try again anyway...

The modeling is done to recently sold prices for non-distressed sales in the vicinity, from the public records, and modeled to specific county records data, including livable sqft, lot size, #bedrooms, #bathrooms, # stories, year built, tax assessed value adjusted for local county rules, last sold price adjusted for the last sold date, and covered parking if in the county records.

It is done in a two-step process, to exclude family transactions and similar, by checking the recently sold against the model, and removing recently solds that don't fit the model well, and recalculating the model before extrapolating estimates for other properties.

The models make no effort to correct for change in condition since purchase.  Those types of changes will need to be adjusted for manually after the fact by the users of the data.

As no two houses have exactly the same data (tax assessed value, sold price & date....), the numerous variables used get weighted differently each time new estimates are made, and thus some go up and some go down, and there is no way to predict which will move which direction at any given point in time, as it is all dependent on the new sales data that comes in since the previous estimate iteration.

And the functions used in the modeling are not linear anyway, so one should not expect linear movement.

For more details on a "similar" method that Zillow has been sued over for alleged patent infringement, see:
US Patent #5361201
  • January 12 2012
  • 1Yes

  • 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 Tony 88
Thanks for replies - so they are off 20%, this does not tell me why one house in the same street is going in a different direction to all it's neighbors.
  • January 12 2012
  • 1Yes

  • 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 jhurlbut
Even Zillow admits that the Zestimate is off by upwards of 20%.  It's only there to be a guide and is not a substitute for an appraisal or a market analysis done by a local Real Estate Agent or Realtor in your area.  If you need an accurate estimate of your home's value, you should seek out one of those individuals.

John Hurlbut, Realtor, ABR, GRI, CFS
John L. Scott Real Estate 
  • January 12 2012
  • 1Yes

  • 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.

  1. 1
  2. 2