We've written thousands of words on this topic already over the years, and I'll try to limit it to only dozens more here. Despite the thousands of words on the topic, I view the DVR landscape very simplistically. These three statements are NOT mutual exclusive:
1. DVRs have significantly decreased commercial viewing
2. DVRs add significantly to the commercial ratings (particularly vs. the live numbers)
3. So far, the Live+7 program ratings offer no predictive benefit in determining which broadcast shows will be renewed/cancelled vs. the Live+SD numbers received weeks earlier.
I don't have any difficulty wrapping my brain around all three of the above being true (because they are!). I know some people have a problem with the first two both being true. They are both true. If there were no DVRs there would be more commercial viewing (#1). But there are DVRs, so some commercials get viewed on them (#2) and it adds up to more than just the live viewing by a significant percentage. At the end of the day, for our purposes, I'm far more interested in the third item above.
The Live+7 program ratings haven't added any predictive value in determining how a show is doing. Whether that's true, at least in part, because some of the DVR viewing is already baked into the Live+SD numbers is inconsequential for purposes of predicting show renewals and cancellations.
It's always harder to figure out what's going on at the cable networks, but here's a general rule of thumb that works well: shows that have very low relative Live+SD ratings don't get saved because of their Live+7 ratings., , , Rubicon, etc, are all canceled. The DVR numbers didn't save them. That of course is also true in the broadcast world (e.g. Lonestar, and ).