Nielsen said a software glitch that attributed some viewership data for broadcast and syndicated shows to the wrong networks has been corrected and that the rating giant is taking measures to assure that the problem never happens again.
In a conference call with reporters, Nielsen said the mistake was negligible – accounting for between 0.1% and 0.25% of all viewing minutes – and was discovered internally as well as by clients.
The mishap dates back to March, but was not caught until after the fall broadcast season had already started. Nielsen said the problem was corrected on Oct. 6 and that it will issue restated ratings to clients beginning with Aug. 18.
Nielsen declined to comment on whether the ratings were attributed to one network – some reports have said that ABC was the sole beneficiary – as it allows its clients to digest the ratings data. Senior vice president planning policy Patricia McDonough said that once ratings are officially released on Monday, the company may have more to say.
Nielsen Global president Steve Hasker added that the discrepancy was tiny, but in the spirit of full transparency the ratings giant felt obligated to release the info.
”Our next priority will be to restate the data for the affected networks for the current TV season,” Hasker said on the call. “...We expect there to be a very limited impact.”
Hasker estimated that about 98.5% of all shows were affected by no more than 0.05 of a ratings point.
The news comes after Nielsen stock fell 4% Thursday after rival ratings measurement company Rentrak announced deals with WPP’s Kantar Media , Group M and with Zenith Media.
Nielsen stock closed at $41.29 each on Oct. 9 (down 4% or $1.72 each) as investors grew skittish that Rentrak’s set-top box derived big data strategy may be gaining a bigger foothold in the TV measurement space. Nielsen shares were up about 2% (87 cents each) to $42.16 in afternoon trading on Oct. 10.
Hasker came out swinging on the conference call, noting that Nielsen doesn’t usually comment on the competition, but felt compelled to do so in this case.
“Our friends at Rentrak has never let the facts get in the way of a good press release,” Hasker said, adding that Rentrak “has never been transparent about their methodology,” so it is difficult to make accurate comparisons.
He argued that Rentrak’s measurement info is not based on census data – he said the Media Rating Council has asked the company to stop using that term. He also noted that Rentrak has no access to demographic data and cannot measure who is watching shows and can only measure viewership from the homes of their partners, or about 40% of the households in the U.S.
Rentrak did not immediately return a call for comment.