(Spotted via Barry at SEL) Mike Blumenthal, who writes a local search blog, has been devoting serious time to understanding the nuts and bolts and what’s under the hood at Google and Yahoo! local. He posts about the quality of basic listings data (poor) in the medical category:
The medical center phone data is in critical condition and in need of intensive care.
Only 2 of the 13 markets did not have listings showing 4 or 5 phone numbers. 18% of all listings showed 3 or more phone numbers despite low verification rates through the Local Business Center. And if you live in Fargo, ND it appears by Google’s account that there are more medical phone numbers than there are doctors.
When I found 5 phone numbers listed for a hospital, I spot checked by calling some of the numbers to see where they went and if the answerer had received erroneous calls. In very limited tests, the numbers went to a department rather than the main desk facility listed and noted receiving a fairly large number of wrong number calls. I think it is safe to assume that any facility with 4 or 5 (and likely 3) numbers listed probably has numbers not for the main facility or that are in error.
Although specific to a “vertical,” this recapitulates the larger challenge of data quality and accuracy in local search. Google’s local business center attempts to involve users — and Yahoo! did this awhile ago — in the updating and correcting of inaccurate local data.
Google gets data from lots of sources and probably has as much or more local data than telcos at this point. But, as Mike points out, there’s still a long way to go.
In my own experience, I’ve often found that listings were missing but generally found that contact details were correct.