The difficulties in talking about TV viewership.

In response to this post on television's surprising longevity, Andrew Gelman pointed out that ratings really have plummeted:

[T]he other day I happened to notice a feature in the newspaper giving the ratings of the top TV shows, and . . . I was stunned (although, in retrospect, maybe I shouldn't've been) by how low they were. Back when I was a kid there was a column in the newspaper giving the TV ratings every week, and I remember lots of prime-time shows getting ratings in the 20's. Nowadays a top show can have a rating of less than 5.

Undoubtedly, there has been a big drop here (as you would expect given that broadcast television used to have an effective monopoly over home entertainment), but has the drop been as big as it looks? There are a few mitigating factors, particularly if we think about total viewership for each episode (or even each minute) of a show and the economics of non-rival goods:

1. 52 weeks a year
It took years for the networks to catch on to the potential of the rerun. You'll see this credited to the practice  of broadcasting live, but the timelines don't match up. Long seasons continued until well into the Sixties and summer replacement shows into the Seventies. With the advent of reruns, the big three networks started selling the same shows twice whereas before the viewers for the first time an episode aired was often all the viewers it would ever have. Should we be talking about the number of people who watched a particular airing or should we consider the total number of people who saw an episode over all its airings?


2. The big three... four... five... five and a half...
Speaking of the big three, when we talk about declining ratings, we need to take into account that the network pie is now sliced more ways with the addition of Fox, CW, Ion, MyNetwork and possibly one or two I'm forgetting.


3. But if you had cable you could be watching NCIS and the Big Bang Theory
A great deal of cable programming is recycled network programming. If we count viewership as the total number of times a program is viewed (a defensible if not ideal metric), you could actually argue that the number is trending up for shows produced for and originally shown on the networks.


4. When Netflix is actually working...
Much has been made of on-line providers as a threat to the networks, but much of their business model current relies streaming old network shows. This adds to our total views tally. (Attempts at moving away from this recycling model are, at best, preceding slowly.)


5.  I'm waiting for the Blu-ray
Finally, the viewership and revenue from network shows has been significantly enhanced by DVDs and Blu-rays


I don't want to make too much of this. Network television does face real challenges, cable has become a major source of programming (including personal favorites like Justified, Burn Notice and the Closer), and web series are starting to show considerable promise. The standard twilight-of-the-networks narrative may turn out to be right this time. I'm just saying that, given resilience if the institutions and the complexities of thinking about non-rival goods, I'd be careful about embracing any narrative too quickly.