TV Ratings by Nielsen Had Errors for Months

By BILL CARTER and EMILY STEEL, NYT, OCT. 10, 2014

Nielsen, the television research firm, acknowledged on Friday that it had been reporting inaccurate ratings for the broadcast networks for the last seven months, a mistake that raises questions about the company’s increasingly criticized system for measuring TV audiences.

The error wound up benefiting one network, ABC, while negatively affecting the others, according to people briefed on the problem. In a telephone call with reporters, Nielsen executives would not confirm that it had resulted in added viewers for ABC, saying they could not discuss individual clients.

An ABC executive confirmed that the error had improved the network’s ratings. As for Nielsen, its executives played down the discrepancy in viewing totals, saying they fell between 0.1 percent and 0.25 percent of the viewing totals.

But it remained unclear how the mistake would affect the billions of advertising dollars based on Nielsen’s ratings, as well as the company’s reputation. And several television and advertising executives expressed degrees of anger and incredulity at both the incorrect ratings and the amount of time — seven months — it had taken to discover the problem.

(More here.)