I have a little joke with myself that goes something like this:
Q: When are a TV show's ratings in trouble?
A: When the fan updating its Wikipedia page uses both live + time-shifted numbers for its viewership numbers.
That may be a somewhat obtuse private joke, so allow me to explain.
First, television ratings are handled by a company called Nielsen. Many of us have, at one time or another, been part of "Nielsen families," wherein our household television viewing habits were monitored for a period of time. Next, "live" ratings are those based upon who watched the program at the time that it originally aired. "Time shift" viewings are those officially counted on stuff like DVR and iTunes, within a reasonable period of time after the original airing. Finally, "rating" is a bit of a dinosaur term these days, as Nielsen pretty much reports a show's viewership these days, and not its actual rating, which is a different number.
Now that that's clear, let's take a look at (as an example) Doctor Who. The highest-rated episode of the (new) Doctor Who program is 2007's Christmas special featuring Kylie Minogue, Voyage of the Damned. It was watched by 13.3 million people in England. I know this because I'm a nerd, and look up television show ratings online. In this case, Wikipedia has the information and, because I've been monitoring this for several years, I can tell you that 13.3 million is the 'live' number of viewers. It was so strong, that whoever goes in and updates the show's viewing figures was happy enough to leave it at the live numbers. In recent years, however, as ratings have begun to slide, I notice that the final number is that of live + time-shift.
You may have noticed that the title of this post refers to The Walking Dead. I'm getting to it. There's no denying the show's popularity. It has a monster audience (no pun intended), especially for a cable show. And, until this month, its ratings have done nothing but grow. I've been following them over the years, and they have trended as follows:
Season 1/series premiere: 5.35 million
Season 2 premiere: 7.26 million
Season 3 premiere: 10.8 million
Season 4 premiere: 16.1 million
Season 5 premiere: 17.2 million
Season 6 premiere: 14.6 million
The season 5 premiere episode is the highest-rated for the show so far. As you'll note, the season 6 premiere is the first time that viewership has dipped for the program at the start of a new season. 14.6 million is still a mammoth number for cable viewership, and shouldn't be sniffed at, but nothing lasts forever. And, for the first time ever in my history of monitoring Walking Dead ratings over the past five years, I saw two curious things. The first was an article that, for the first time I can recall, notated what an episode's ratings were if you included time-shift viewing (19.5 million in the case of the season 6 premiere). Second, I noticed that the Wikipedia page was updated to include this number (it has since been changed back to the live number, ahem).
The Walking Dead has always made its ratings headlines with its live numbers. The fact that the press and fans have taken to including time-shift numbers is a sign that the live numbers may not ever be what they once were. This isn't by any means out-of-the-norm. Almost all shows (unless they go out on top like Andy Griffith or Seinfeld) see declining ratings toward the end of their run. The problem (if you want to even call it that) is of an archival nature. If you've always notated a show's ratings based upon what its live rating was, then is it accurate to have later episodes include time-shifted numbers? Doesn't that make for an uneven comparison?
If there is one takeaway from the situation of Walking Dead's now-declining ratings, it's that the show needs to think seriously of its exit plan. As I remarked earlier, nothing lasts forever. Eventually, the show will come to an end, as all good stories must. From an artistic point-of-view, when should it end? Note that the creator of the comics has said that he has story-line ideas for at least a hundred more comics. That's all well and good, but comic books and TV shows are different beasts. Also, from a commercial standpoint, the fact that Walking Dead has been such a massive hit begs the question: How long do you want it to go before its ratings dwindle down to nothing?
After all the hype, all the eyeballs glued to TV screens, all the appointment television viewing, the intense interest in what comes next, do the showrunners want to see their program finish-off at a point when they're back to numbers in the ballpark of when it began? That would mean a drop-off of well over half its peak viewership. Is that what they want -- to wrap-up a show that, by the time it ends, nobody really cares about anymore?