In an LA Times story about how the networks are desperate for young viewers CBS's head of scheduling Kelly Kahl said: "You can't read the next day's [ratings] numbers and take a real meaningful read from them anymore."
We have no axe to grind with Mr. Kahl. All he's ever done is entertain us on Twitter and schedule the only network that didn't have the Super Bowl with 18-49 ratings growth this season. Sure, technically that growth is a PR bonus born of statistics since through last Sunday, CBS's average number of 18-49 viewers in primetime was exactly the same as last yea. But because the Nielsen universe estimate for the number of TV viewing adults 18-49 shrank this season vs. last, CBS has eked out a small gain in terms of the rating.
Like any reasonable person trying to gauge the popularity of the show, I too agree that the daily ratings aren't very meaningful in gauging total popularity. But advertisers don't care about total popularity, they care how many people saw the commercials. From what we can tell, the daily program ratings usually track pretty closely, relatively speaking, with what advertisers actually care about.
So the question is "meaningful to what?" If it's to the total popularity of the show, nope, those numbers aren't very meaningful. But the daily ratings have consistently been useful to figuring our what a network's best and worst shows are and what shows will be renewed and canceled. That usefulness hardly seems coincidental so from that perspective useful = meaningful.
Do Modern Family and The Big Bang Theory add truckloads of viewers on DVR past the day they air? Of course they do. But we don't need to see those numbers to know they're their networks highest rated shows. Whether it's the next day or two to three weeks later when the Live+7 ratings come out, the result, relatively, is the same. Did CBS wait for the Live+7 numbers on How To Be a Gentleman came out before it canceled the show? Nope.
Unforgettable's Live+SD ratings rank it 59th out of 154 English language primetime broadcast shows this season. With the extra six days of DVR viewing, it rises to tied for 57th. But if CBS renews Unforgettable we might have to concede something mattered more than the daily ratings -- even if it wasn't the DVR ratings.
Based on the daily ratings, we're very clearly not expecting Unforgettable to be renewed.