NEW YORK (AP) — The Nielsen company said Tuesday its report last week that ABC's evening newscast had broken a 263-week winning streak by NBC was incorrect.
The ratings reversal is the most visible example of a software error that Nielsen said had affected its measurement of television audiences since March. Because of the error, in many cases Nielsen had overestimated ABC's viewership in comparison to its rivals.
It had been cause for celebration at ABC when Nielsen reported that for the week beginning Sept. 29, "World News Tonight" had averaged 8.42 million viewers to 8.25 million for NBC's "Nightly News." NBC's newscast, anchored by Brian Williams, hadn't lost a week since 2009.
Nielsen, after fixing the software error and checking the numbers again, said that in fact ABC's newscast that week had 8.11 million viewers compared to NBC's 8.28 million.
So NBC's winning streak stretched to 264 weeks. Actually, it now stands at 265, since the company said NBC also won last week.
Bragging rights are important at the flagship telecasts for network news division. The perception that one network is gaining and the other is sinking also has financial repercussions, as advertisers look to hook up with the hot broadcast.
"We rely on Nielsen like everybody else in the industry and need accurate information," said ABC News spokesman Jeffrey Schneider.
The Nielsen flub "in no way changes the obvious momentum" of "World News Tonight," which has been anchored since the beginning of September by David Muir, Schneider said. ABC has won several weeks among the 25-to-54-year-old viewers who are considered extra valuable to advertisers, even as most evening news viewers are older.
"We are pleased that the corrected numbers confirm that 'Nightly News' is the No. 1 news broadcast in America," said Erika Masonhall, NBC News spokeswoman. "We remain, first and foremost, committed to our viewers and bringing them a broadcast with credible, authoritative news they can trust."
Nielsen has been going over its records for the past few weeks to determine if the software error caused other high-profile changes in the rankings.