Let’s get this out of the way first: C-SPAN is a non-commercial channel dedicating to covering public policy in the U.S. (and occasionally abroad). It does not have any ads on its airwaves, and is funded by the cable industry as a public service.
Because of that, C-SPAN is not rated by Nielsen, which has a de facto monopoly on commercial television ratings. Why would C-SPAN pay to be rated when it doesn’t have any commercials? Still, as Brian Stelter in the NY Times notes, C-SPAN is still tracked by the ratings companies, including Nielsen competitor Rentrak, which measures data from set-top boxes on DISH Network, DirecTV and Charter Communications.
Stelter was able to obtain some of the data, which suggests that C-SPAN2′s ratings rose precipitously during a day-long speech on the Senate floor by Ted Cruz (R-TX).
Rentrak’s nationwide audience projections are based on anonymous data from set-top boxes in about 12 million homes served by companies like DirecTV, Dish Network and Charter. A 1.0 rating is approximately 1.15 million households, and C-Span’s average daily rating in September was 0.017, meaning 19,550 households were watching at any given time. C-Span2’s average was 0.012, or 13,000 households. Those averages are undeniably low. But Bruce Goerlich, Rentrak’s chief research officer, observed that the ratings “popped up” toward the end of the month as a government shutdown loomed.
And since C-Span is a utility of sorts, its real relevance is measured in its cumulative ratings: the number of households that watch at one time or another. In September, nearly 9 million households tuned in to C-Span at least once, according to Rentrak’s projections, and about 5.3 million households tuned into C-Span2.