Wed 27 Sep 2006
Kevin Boer of In The Trenches, a real estate blog out of the Bay Area, got me involved in some hare-brained scheme to track the accuracy of a random sampling of data from Zillow in each of our markets and compare those to county data v.s. our local MLS.
Ask anyone who knows me…. the first thing they think of when you mention “Marlow” is mathematical theory, multiparameter estimation, statistical modeling and asymptotic approximations. So I jumped at the chance to help.
Interestingly enough, my data and Kevin’s netted almost the same results. He’s looking for others around the country to assist and add to his chart, so if interested, contact him at kboer@apr.com
In response to yesterdays post “Trulia expands nationwide“, Dustin Luther put together a Excel spreadsheet that examines not only how many listings each service has, but also how many “accurate” listings each service has for one zip-code (98117) in Seattle. He found out several interesting things like (1) Redfin’s zip-code search is broken (i.e. a search on 98117 returns results for other zip codes like 98203 and does not return all the homes that Redfin has with a zip-code of 98117), (2) confirmed that Realtor.com does not have any Windermere listings and (3) Trulia has a long way to go before they are comprehensive. If someone wanted to take this data and add one more zip code in some other part of the country, he’ll post the results. Email him at Dustin@RainCityGuide.com
One of the results I came up with in searching home for sale in “Redmond, WA” was that Yahoo had almost twice as many listings as the MLS, yet Yahoo is using a direct feed from the MLS via Prudential Real Estate. They could be using different search parameters, including “pending” sales or adding listings from other sources (i.e. a feed from Homes & Land Magazine), or not expunging expired listings, but I haven’t figured that out yet. I’ll try to research that and publish my findings here.
** NOTE **
As of 9am 9/27, the Rain City Guide site is down, due to a change in service provider. Dustin had mentioned he was having hosting problems a few days ago, and I expect him to get back up online soon.
September 27th, 2006 at 11:27 pm
[…] Marlow Harris at 360 Digest and Kevin Boer at In the Trenches have been zeroing in on the accuracy of Zillow.com’s Zestimates. This has been Kevin’s project from the beginning, and a visit to his weblog is very instructive. […]
September 30th, 2006 at 9:14 am
I think with Property Sharks collaboration with Trulia…they could be a serious threat to Zillow….also big difference comparing past historical sales data and up to the minute data.
October 20th, 2006 at 9:36 am
Word on the street is Zillow and Trulia are going to combine companies and issue a IPO