Growing multicast channels may be big factor in PBS ratings mystery

Stirrings of audience life in multicast channels may the big reason why the national Nielsen ratings acquired by PBS have been rising even though local Nielsen numbers are still generally slipping.

Audience analyst Judith LeRoy, co-director of TRAC Media Services, says that Nielsen includes multicast channels' viewers in national PBS numbers, which are network-oriented, while they are counted as separate channels in local data, which are more strictly channel-oriented. Multicast channels such as Create, World, V-me and some locally packaged channels tend to have no measurable audience or a fraction as many viewers as the largest PBS channel in town, but small increments from two or three additional channels per market could mount up quietly, given that most stations don't see the data because they'd have to pay extra to Nielsen.

The gain is good news for public TV if -- like Discovery and other big multichannel cable programmers -- PBS can recapture some of their viewers who are dispersing to other channels.