"I am curious why your data show only 43,507 Texas listings while Zillow and Realtor.com have 79,344 and 146,265 for Texas, respectively. I realize some listings remain on these sites for several weeks after they are sold for marketing reasons, but that's still a substantial difference. And most Realtor.com listings come from the MLS, or so I am told."
Gerald Klassen, research data scientist here at the Texas Real Estate Research Center, shed some light on the topic.
"Our count of 43,507 is the number of active status listings open as of the last day of the month," he said. "We count only single-family detached, condo, and townhouse listings. We use this figure to calculate months inventory, which tells you how long it would take for the market to clear if no new listings came into the market."
Zillow and Realtor.com, meanwhile, provide a count of listings as of the point in time a person is searching their website. Before month's end, many of the homes will be sold and a few will be taken off market. New listings are continually added, mostly at the beginning of a month.
"I just filtered by property type on Realtor.com, and there are currently 98,599 single-family, condo, and townhouse listings in Texas," Klassen said. "If you hide the pending/contingent listings, that figure drops to 39,452 in active status. That's not far from what we're showing as active listings on our website. What is amazing about this count is that more than half of the listings on Realtor.com are in pending or contingent status. What we have witnessed in this pandemic housing boom is that the average home’s time on the market has fallen while the average time to close has increased. People are finding it hard to get the services required to close their home sale/purchase."
The difference between the Center’s active listing count and that of Zillow or Realtor.com can be accounted for by time of search, property type of the listing, and listing status.
"It is amazing to think that we can have record home sales and so few active listings," Klassen said. "Off-market listings in many areas are down 50 to 70 percent compared with last year. That means that pretty much everything that comes into the market exits via sale."