(Update: Nickelodeon now says it erroneously reported that kids' viewership is up overall this season, and that overall viewership is in fact down. It still stands by its Nickelodeon data, however.)
Nickelodeon is down in the ratings, and in the dark about why.
After 16 years of dominating children's television, the network finds itself in the midst of a mysterious ratings slide serious enough to drive concerns about its parent company's stock and prompt an investigation with Nielsen.
In just-released November ratings, Nickelodeon was down 19 percent year-over-year in ratings for viewers age 2 and older. In October, its ratings fell 13 percent.