Zillow Improves Z-estimates; Adds NCI’s Listings

Zillow has been adding feature-after-feature and is about much more than its initial calling card: the “Z-estimates” of local house values. But Z-estimates are still a core feature, and they still have the ability to infuriate/please Realtors when they come up above (or below) actual market value. My wife the Realtor is still seething about one Z-estimate that came in $40,000 below her asking price (although she actually loves Zillow).

Apparently, the modeling that goes into Z-estimates has been in need of some serious improvement. According to Zillow, recent improvements to the modeling have improved their accuracy by 12 percent nationwide, with higher increases in top real estate markets such as San Francisco (18 percent), Miami (21 percent), Los Angeles (22 percent), and Atlanta (28 percent).

Does it mean that Atlanta listings were only accurately gauged by Zillow 72 percent of the time? That’s worse than United Airlines on-time record. But that is probably not the case. Most likely, the improvement is incremental (i.e. not so dramatic).

Zillow notes that most of the improvements have been centered on adding “20x” more information to each Z-estimate. The addition of user submitted home facts (number of bedrooms, bathrooms, additions, renovations etc.) are at the core of the improvements. The new Z-estimates can also be broken down at the neighborhood level, instead of just county-wide levels.

In other Zillow news, released to coincide with the Inman Real Estate Connect conference in New York City, 500,000 residential listings have been added from NCI, which publishes The Real Estate Book and other titles. On Kelsey’s stage at ILM:97, NCI CEO Dan McCarthy appeared with Zillow’s Jorritt Van de Meulen and revealed that some type of deal was in the works. Zillow had previously announced listing deals from over 283 newspapers, as well as several brokerages.

Zillow CFO Spencer Rascoff told my Kelsey colleague Michael Boland that more listings and user participation will be the number one factor to continuing to improve Z-estimate accuracy. “Everything that we do on the consumer side is about increasing unique visitors and levels of engagement,” says Rascoff. “This lets us drive more page views and more time on our site in order to have more ad inventory to give back to our advertisers.”