Nielsen Corrects TV-Viewing Data

Nielsen Holdings NV said it erred late last month when it reported an overall increase in the number of children watching television this fall, but it continues to be in disagreement with Viacom over the accuracy of its TV ratings for Viacom's Nickelodeon children's channel.

The TV-ratings giant now estimates the number of children ages 2 to 11 that watched traditional television channels at any given minute this TV season through Nov. 19 fell 2.9% when compared with last fall, rather than rising 1.7%, as it had initially indicated in data prepared for The Wall Street Journal. Nielsen's prior estimate of the audience increase had put the spotlight on Viacom, which has suffered a recent sharp drop in viewership for Nickelodeon, a big source of ad revenue for the company. Viacom has described that drop as a "glitch." Other TV channels aimed at children haven't experienced similarly steep declines. Nielsen detected a mistake in the overall-viewing data provided to the Journal after Viacom contacted the ratings company to question its numbers, Nielsen and Viacom executives said. Nielsen explained the error by saying it had neglected to "apply a standard adjustment" to fall 2010 data in order to make it comparable with this fall's numbers.