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I live in the Midwest and our home prices are relatively flat over the last decade for the city I live in. 18 months ago I noticed that my zestimate was inflat

I live in the Midwest and our home prices are relatively flat over the last decade for the city I live in. 18 months ago I noticed that my zestimate was inflated and rose to 2x my appraised value of my home (refinanced that year). I looked into it and noticed that Zillow was doubling the sales price of recent homes. This was the main issue. I reported it to Zillow and some in customer service said their engineers would look into it. Only in the last few months have th Zestimates come back to reality. I bring this up because I was curious as to how this would play out for my city and home prices. Would this increase prices for the area or would realitors ignore the data and go with what they knew would make sense. I haven't seen a huge increase in prices nor have a done any study of it. But just the idea that a bug could cause such a calamity for a least the size of a city was eye opening.

qxamak 10y ago
I have a friend who is a realtor and we talk about this subject occasionally. My understanding is that most realtors will recommend using Zillow to "get a feel" for the market. But Zillow's estimates are only as good as the data that goes into them. Usually, data for an area is publicly available and up-to-date, but sometimes it's very old or just plain wrong. I think Zillow claims their estimates to be within 10% of actual sale price. To me, that figure seem to be pretty good from a data analysis stand point; but 10% of the value of a house is a lot of money for even a modest home. Most realtors used closed databases, like MLS, to document sales and compare area housing prices. I believe MLS data is typically manually entered and verified (I'm not 100% sure about this though). I believe there is also a lot of extra metadata added to MLS listings that Zillow can't get from public records. Realtors also tend to look at property tax assessments for their areas in order to gauge market trends (just like Zillow does, except without a hidden algorithm).

qxamak 10y ago

I have a friend who is a realtor and we talk about this subject occasionally. My understanding is that most realtors will recommend using Zillow to "get a feel" for the market. But Zillow's estimates are only as good as the data that goes into them. Usually, data for an area is publicly available and up-to-date, but sometimes it's very old or just plain wrong. I think Zillow claims their estimates to be within 10% of actual sale price. To me, that figure seem to be pretty good from a data analysis stand point; but 10% of the value of a house is a lot of money for even a modest home. Most realtors used closed databases, like MLS, to document sales and compare area housing prices. I believe MLS data is typically manually entered and verified (I'm not 100% sure about this though). I believe there is also a lot of extra metadata added to MLS listings that Zillow can't get from public records. Realtors also tend to look at property tax assessments for their areas in order to gauge market trends (just like Zillow does, except without a hidden algorithm).