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Ask HN: Zillow and redfin estimates overtime, comparison?

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Ask HN: Zillow and redfin estimates overtime, comparison?

#1
Hi, Is anyone aware of a service/website which shows how zillow and redfin estimates vary overtime(for a given address or region). Ideally, I want a report which alerts me when zillow modifies my home estimates. More generally, what are some services for tracking accuracy of automated valuation models?

Re: Ask HN: Zillow and redfin estimates overtime, comparison?

#3
post #2

I am not aware of any services but they have an API. I think it'd be skirting the tos to save it, but if this is just for personal use it might be ok. https://www.zillow.com/howto/api/HomeValuationAPIOverview.ht...

As far as general tracking of avms I don't know of any and the incentives are not properly aligned to have them set up (avm provider doesn't want to show inaccuracies).

Zillow used to show percentage error but it was a web page showing inaccuracies by zip.

Re: Ask HN: Zillow and redfin estimates overtime, comparison?

#4
post #3
post #2

I am not aware of any services but they have an API. I think it'd be skirting the tos to save it, but if this is just for personal use it might be ok. https://www.zillow.com/howto/api/HomeValuationAPIOverview.ht...

As far as general tracking of avms I don't know of any and the incentives are not properly aligned to have them set up (avm provider doesn't want to show inaccuracies). Zillow used to show percentage error but it was a web page showing inaccuracies by zip.

I agree with the incentives part. But, apparently, some AVMs(not necessarily Zillow) are used by mortgage lenders to adjust their risk models. In such cases, I would assume lenders will first want to find out information about accuracy(through third parties).

You are right that zillow used to show accuracy by zip code. But I am looking for more granular info.

Re: Ask HN: Zillow and redfin estimates overtime, comparison?

#6
post #3

Earlier quoted context omitted.

As far as general tracking of avms I don't know of any and the incentives are not properly aligned to have them set up (avm provider doesn't want to show inaccuracies). Zillow used to show percentage error but it was a web page showing inaccuracies by zip.

I agree with the incentives part. But, apparently, some AVMs(not necessarily Zillow) are used by mortgage lenders to adjust their risk models. In such cases, I would assume lenders will first want to find out information about accuracy(through third parties). You are right that zillow used to show accuracy by zip code. But I am looking for more granular info.

Sure, I bet the AVMs share their accuracy to people that pay them, but I bet not to folks who don't (consumers).

Anyway, hope this post turns up some useful info.

Re: Ask HN: Zillow and redfin estimates overtime, comparison?

#7
Zillow is not accurate at all. In my market, Redfin has been accurate to within 5% of the price, up or down. However, Redfin is a real estate agency, so they use their estimates and have access to data that Zillow doesn't, and they will adjust the algorithm at a neighborhood level.

Zillow is merely a real estate value estimator (they don't use sufficient data to earn the right to call themselves an appraiser nor do they provide sufficiently updated listings to justify calling them a listings service).

Re: Ask HN: Zillow and redfin estimates overtime, comparison?

#8
Zillow will give you monthly updates on their estimate of your house, and they show a history of their estimate when you drill into a house. When I listed my house for sale last month their estimate shot up immediately to closely match the offer price, so worth being skeptical.
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