The further removed listings data is from a multiple listing service source, the more likely its price or status is inaccurate, according to a white paper from real estate search and technology site Trulia.
The company analyzed more than 430,000 listings submitted between Feb. 15 and April 15, 2011, to Trulia Direct Reference, the company’s free system that is designed to identify discrepancies between real estate listings from MLSs and listings on third-party syndication sites.
The system officially launched in March. The listings analyzed came from syndicators, franchisors, brokerages, agents and MLSs.
Trulia’s analysis found that third-party syndicators of listings data that did not come from an MLS had an error rate of 21.3 percent for either a listing’s price or status. Real estate professionals submit data to these sources but often don’t return to update their listings, Trulia said.
The results show the value of syndication by MLSs, Trulia said.
"An MLS that does not syndicate for their membership inadvertently creates an environment that results in a significant increase of disparate data sources resulting in less accurate date online," the paper said.
Third-party resyndicators of MLS data had a 10.2 percent error rate, while direct feeds from brokers had a 5.6 percent error rate, and direct feeds from franchises had a 3.9 percent error rate.
In addition, Trulia found that MLSs that require their brokers to opt out of syndication if they prefer not to syndicate their listings rather than opt in if they do, reduced price or status errors by more than 60 percent.