Eager to demonstrate how it’s a brave new world out there (or to provide legitimate excuses for why their ratings are down), the broadcast nets have begun to include DVR viewership levels in their daily and weekly ratings releases. CBS is even announcing estimates on DVR playback; for instance, the network is projecting that delayed, DVR viewership of the new Big Bang Theory could boost the show’s 18-49 rating by 10 percent and its 18-34 by 14 percent. (Ooo-kay. And they figured that out … how?) Insiders admit that this isn’t an exact science, but it’s certainly worth guesstimating since DVR penetration in Nielsen homes has jumped from 8.54 percent last year to 19.43 percent this year.