Billions of ad dollars at stake in Nielsen ratings glitch

The ratings wars for the big networks are in full swing — and Nielsen just said the numbers are wrong.

The problem: Ratings may have been "misattributed," Nielsen said. That means people may have been watching a show on one network, but the credit went to another.

The cause was a software glitch, and Nielsen said it began in March.

Nielsen has a lock on measuring who's watching what, and its ratings determine billions of dollars in ad sales -- and who gets to keep their jobs.

"This is the equivalent of an earthquake. When you can't trust the ground you're standing on, it's disorienting," a network insider said. "What else has gone wrong that we don't know about?"

The error did not affect ratings on cable or local TV ratings.

And Nielsen said the impact shouldn't be too big: Most programming would see a difference of 0.05 of a ratings point.

However, even tenths of a ratings point mean a lot in terms of advertising rates.

Nielsen said it caught the issue because of the uptick in audience that came with the fall TV season.

The Nielsen mistake may be the answer to why ABC has seen abnormal gains in reported ratings in recent weeks, though Nielsen did not specify the impact on any one network.

In a statement, ABC said: "Our entire industry relies upon Nielsen for accuracy and veracity, and we hope that they can quickly resolve this issue. We're confident that the momentum we've seen across the network so far this season will continue."

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