The Interactive Advertising Bureau late last week issued an open letter to comScore and Nielsen//NetRatings requesting they submit to a third-party audit of their measurement processes.

Although the IAB has spent years pushing the two major Web audience measurement services, an audit by the independent Media Rating Council is more likely now because there's a sense of urgency and greater industry support, said Randall Rothenberg, president and CEO of IAB since January. The issue of bad metrics, he said, was the resounding issue that IAB members named when he assumed the job.

"The IAB and the MRC have been asking for this since 1999 and they haven't even established a timetable," said Rothenberg, alluding to the measurement firms. "Tensions are running high as the Internet becomes the center of all marketing."

The Association of National Advertisers is now onboard supporting the audit, while Rothenberg said he expects the American Association of Advertising Agencies and other trade organizations to join the fight shortly.

The goal of the IAB and its industry members is to achieve transparency in audience counts and to revise out-of-date methodologies, according to Rothenberg, adding that "despite a multiplicity of reported discrepancies in audience measurements, comScore and NNR each has resisted numerous requests for audits by the IAB and the Media Rating Council since 1999."

To establish the source of apparent discrepancies between the audience measurements of comScore and Nielsen and those of the server logs of the IAB members, the IAB has asked that both comScore and Nielsen obtain audits of their technologies and processes by the Media Rating Council.

Media companies have often complained about large discrepancies between their own log files and panel companies' versions of their traffic.

In addition, the owners of sites serving niche audiences say their traffic can be ignored completely because panels represent a miniscule fraction of the total Web audience and do not accurately reflect all segments.

"All measurement companies that report audience metrics have a material impact on interactive marketing and decision-making," Rothenberg wrote. "Therefore, transparency into these methodologies is critical to maintaining advertisers' confidence in interactive, particularly now, as marketers allocate more budget to the platform."

Neither comScore or Nielsen responded to requests for comment regarding the IAB's letter.

Media buyers applauded IAB's efforts despite the fact that they rely on a number of other market indicators besides comScore and Nielsen.

"We need those tools to be as [accurate] as they could possibly be, so I don't know why they'd resist an audit," said Sarah Fay, president of Aegis' interactive ad agency network, Isobar, U.S.

"But," Fay added, "At the end of the day, their numbers are used more as a directional tool rather than a holy grail for our decision making."

In the letter, Rothenberg asks for a summit meeting with the IAB's Board of Directors on interactive audience measurement, along with an agreement to a near-term timetable for independent audits and accreditations of comScore's and Nielsen's companies' interactive-audience measurement processes.

This news story is important. I recommend that everyone read it.