Ratings Firms Respond to IAB Complaints

NEW YORK The leading Internet measurement services have responded to an unusual public challenge by the Interactive Advertising Bureau to submit to third-party audits.

Both ComScore Media Metrix and Nielsen//NetRatings said in separate letters that they are in the process of securing third-party certification of their methodologies. Nielsen//NetRatings said it has already completed the Media Ratings Council’s pre-audit. ComScore said it is in the midst of an audit by the Advertising Research Foundation.

In his recent “open letter” to the measurement firms, IAB CEO Randall Rothenberg asserted both had “resisted numerous requests for audits” by the IAB and MRC.

At issue is the efficacy of the panel-based approach used by both companies, which track the Web habits of a sample audience and then extrapolate to project numbers for the entire Internet audience.

The IAB represents a wide swathe of Web sites that sell advertising. Web sites have complained that these services underestimate their audiences as reflected in their own log files.

The ratings services have dismissed the complaints as a misreading of server stats, which count the same visitor coming from a work and home computer twice, or visitors who regularly clear their cookies. ComScore, for example, issued a report last week that claimed cookie deletion causes sites to overestimate their audiences by as much as two times their actual traffic.

The need for accurate audience measurement is critical as larger chunks of ad budgets move online. Media planners use ComScore and Nielsen//NetRatings—the latter owned by the parent company of Adweek—when constructing media plans. Smaller sites and those with younger users have claimed they suffer because their visitor statistics are incorrect.

In his letter, Rothenberg said the Web risked not living up to its promise of heightened measurement and accountability if the industry does not work out the discrepancies.

“To persist in using panels that potentially undercount or ignore the diverse populations that are the future of consumer marketing is to deny marketers the insights they need to build their businesses,” he wrote. “And it certainly appears to us as if these audiences are being undercounted or disregarded.”