With PBS, we measure in a more customized way that matches their unique needs. Just as PBS does not distribute programs in the same way that broadcast networks do, we do not provide ratings in the same way. For example, commercial broadcast network affiliates typically air network programs at the same day/time as other affiliates. PBS stations often pick and choose which programs to carry and subsequently frequently schedule them at different times. And, PBS does not have the same need to understand audiences to satisfy advertiser needs. The result is that PBS identifies those programs for which it wants national audience estimates and provides Nielsen with a line-up of stations around the country that air that program along with days and dates the shows air. Nielsen then verifies that the stations carried the show using electronic verification and produces audience estimates. This is a more time-consuming method than is used with commercial broadcast and cable networks – and is only done for those national programs that PBS selects. National convention viewing to PBS has not been reported by Nielsen. Any estimates that PBS has issued are their own, based on procedures that PBS would have to explain.

C-SPAN is not included because Nielsen does not measure and report C-SPANs’ audiences. Many cable networks choose not to have Nielsen measurement for a variety of reasons specific to the network. For example, the home shopping networks do not subscribe to Nielsen. It is probably safe to say they measure their success by other means.