I don't know about "zestimates", but they seems to not be able to do something as simple as email address verification properly. Admittedly, based only on the five email's I have received from realtors in North Carolina just this morning (I live in Nebraska and have no plans to move any time soon).
How Bad Are Zillow “Zestimates”?
61–70 of 208 posts
Re: How Bad Are Zillow “Zestimates”?
#62While we're at it, lets also figure out why my Zestimate dropped $40k overnight two months ago. If I was planning to sell, I would have a huge problem on my hands. On top of it the Zestimate chart shows no indication that they dropped it $40k. Aiming to fix the number is a fool's game : my "private home estimate" on my owner dashboard is 23% higher. Its a worthless number, and they should stop trying to manipulate th…
From time to time, Zillow rejiggers (that's a technical term) their algorithm, resulting in sudden readjustments of estimates. Given that the Zestimate itself is presented as a fairly wide range, the error margin is hardly hidden. Also, it is important to remember that no appraiser from Zillow has actually looked at your house; the data is drawn entirely from sales data, public records, and volunteered information. S…
With how slow real estate moves, thats saying a lot.
Re: How Bad Are Zillow “Zestimates”?
#63I am quite disappointed in the research that went into this article.
(1) Author discovers that Zillow has a specific claim about accuracy: "around 90% of the listing Zestimate is “Within 20% of Sale Price” of the home". Author then gripes that this is "a really large margin for error". Really? Because I was prepared to praise Zillow for such honest and clear reporting. It only costs a few hundred dollars per home (Zillow covers nearly every home in the US) to get a professional to produce an assessment, and these assessments are usually only a little more accurate than what Zillow is claiming.
(2) Author pulls up tables from Zillow showing a median error. Which is an excellent way to analyze this and is (I think) extraordinarily small. Author then proceeds to do other stuff.
(3) Author decides to verify the values by checking a total of NINE houses. Is the accuracy of that test expected to impress us? Furthermore, one of these 9 is rejected because "(obviously a data glitch or input error. Dismiss this result)" -- but that's the whole POINT of using median error; it isn't affected by outliers.
(4) Author finds that all of the values (all 3 of them) in Staten Island were pretty far off. Author asks professionals who say that the local market o Staten Island is behaving quite unusually at the moment. Reporting on this is the only thing I think the author did right.
Re: How Bad Are Zillow “Zestimates”?
#64Earlier quoted context omitted.
> What's puzzling is that they also bumped up the historical Zestimates There are two things a "historical estimate" could mean: 1) What did Zillow say the value was on day X? 2) What does Zillow now think the value was on day X? You and others seem to be thinking of (1), but I think Zillow actually is doing (2). Since the goal is to figure out what the house is worth and how its value has changed, I think (2) is act…
(2), of course, has the advantage of obscuring past mistakes and producing a nice smooth chart.
Unless you think they should never update their algorithm, approach (2) is just making the chart consistent with itself.
The useful part of these charts isn't really the current Zestimate, but rather the trend line of the home values, especially at the neighborhood level.
If you don't recalculate the historical values, then you break the ability to see the trend line.
If you really want to see the results of previous models, then the way to do that is to plot a separate line for each model, but you can see why they wouldn't want to do that from a product perspective.
Re: How Bad Are Zillow “Zestimates”?
#65I don't have an opinion on whether zestimates are accurate. But this blog post has 9 samples from only 3 cities. And the author seems to be making claims based on that. This is a lame "thought leadership" post as a subtle ad for his company. At least give me 10-20 homes in each of 10-20 cities if you are trying to convince me of something systematic.
This is a good example of how commonly and easily 'faux' statistical evidence can incite large reactions primarily composed of anecdotes.
Re: How Bad Are Zillow “Zestimates”?
#66I don't have an opinion on whether zestimates are accurate. But this blog post has 9 samples from only 3 cities. And the author seems to be making claims based on that. This is a lame "thought leadership" post as a subtle ad for his company. At least give me 10-20 homes in each of 10-20 cities if you are trying to convince me of something systematic.
The only really interesting thing I saw in this post was the discussion with realtors. It's significant that Zillow uses long-term averages, and therefore can't price in abrupt market shifts even once they're common knowledge. If nothing else, it implies that "Zestimates" are a bit dubious in tight urban markets where high variance is more possible. Of course, it also looks like Zillow is aware of that challenge.
The ostensibly data-driven part was by far the least convincing section - as soon as I saw the sample size I decided it was nothing more than a starting spot-check.
Re: How Bad Are Zillow “Zestimates”?
#67Zillow is beyond useless. My property consists of 4 legal "lots", two of which the house physically occupies. Each lot is assessed separately by the gov't for tax purposes. The "Zestimate" considers only the lot associated with the street address. So about 40% of the property valuation is ignored.
Second, my house is lakefront. Lake frontage is probably the single biggest factor in valuing the property. Yet Zillow ignores lake frontage as a feature. In fact a recent check of so-called "comps" included no lakefront homes at all. A complaint to Zillow was met with a yawn and a "well its just a number people can use as a starting point, and real estate professionals in the area will know the particulars." So basically they told me the "Zestimate" has no value and they know it.
Re: How Bad Are Zillow “Zestimates”?
#68SF Bay area, I've had 3 formal house assessments, & each time they "start with" Zillow et al to look at "reasonable values in the neighborhood". Which seriously affects your ability to refi, etc. So Yeah Zillow has an effect. It's worth it to create a login & enter in your upgrades, so your ZESTIMATE goes up.
I'm pretty sure that when they say they start with Zillow, they are referring to the feature where it shows recent past sales in your neighborhood, which is an entirely legitimate input into determining a formal appraisal.
Re: How Bad Are Zillow “Zestimates”?
#69While we're at it, lets also figure out why my Zestimate dropped $40k overnight two months ago. If I was planning to sell, I would have a huge problem on my hands. On top of it the Zestimate chart shows no indication that they dropped it $40k. Aiming to fix the number is a fool's game : my "private home estimate" on my owner dashboard is 23% higher. Its a worthless number, and they should stop trying to manipulate th…
My house is recently on the market and the Zestimate and Redfin estimate dropped by 50k the day we listed. It's still higher than we listed but much closer to our number. I think we priced it fairly as we are having plenty of interest but I wonder what would be happening if it didn't change.
Re: How Bad Are Zillow “Zestimates”?
#70I don't have an opinion on whether zestimates are accurate. But this blog post has 9 samples from only 3 cities. And the author seems to be making claims based on that. This is a lame "thought leadership" post as a subtle ad for his company. At least give me 10-20 homes in each of 10-20 cities if you are trying to convince me of something systematic.
It's even worse than that, really. The author actually concedes that Zillow's listed median error is accurate--but then cherry picks a few cases that are outside that margin, and uses these to make sweeping claims about how its time to stop using Zestimates. But, of course, a few cases outside the median error, here or there, are virtually guaranteed to exist no matter how good the model is.
It seems to me that the real news here is actually that the Zillow median error is really good, given the data they have to work with and the scale on which they are operating. Of course, this does not mean that the Zestimate will be valuable in all cases. Individual buyers, sellers, and their agents and appraisers will often have fer better information about any given home. But everyone should have realized this already.