After reviewing a handful of websites, Fair Isaac has reported 10-15 percent of the advertising traffic is "pathological," indicating a likelihood of click fraud, said Joseph Milana, the company's chief scientist of research and development.
"It's still an early result," Milana said. "The question remains about how broad the problem is in the entire marketplace."
Milana said click fraud on Google and Yahoo's respective websites isn't the problem — it's when the two companies deliver the ads to other sites.
"They just don't know what happens beyond their own firewalls," Milana said.
Google and Yahoo have consistently ridiculed double-digit click fraud estimates as the handiwork of search engine consultants trying to drum up more demand for their services by alarming advertisers, according to a report.
Both companies maintain that its engineers and filters identify all but a small portion (Google said 0.02 percent) of flagged click fraud.
