Ask HN: Zillow and redfin estimates overtime, comparison?

6 points by sdsdsdsdsdsds 8 years ago | 10 comments

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?

gamblor956 8 years ago |

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).

BeetleB 8 years ago |

With Zillow, you can just track a home (don't recall how - maybe just "Save" will work?). You can have it periodically email you reports on the home, which will include the value estimate.

joezydeco 8 years ago |

Ideally, I want a report which alerts me when zillow modifies my home estimates.

So sign up with Zillow and "claim" your home, then subscribe to email updates. You'll get mailed weekly with your "estimate". Using quotes there because, like gamblor956 says, the values are complete bullshit.

mooreds 8 years ago |

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...

mooreds 8 years ago | |

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.

sdsdsdsdsdsds 8 years ago | | |

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.

itsdrewmiller 8 years ago |

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.

bsvalley 8 years ago |

You could build a simple web crawling tool pointing to the URL of your house on zillow or redfin (trigger it just once a day).

Zillow estimate is way off by the way...

chrisgoman 8 years ago |

How much are you willing to pay? Are you expecting this to be a free service? There is a company called Altos Research