There are lots of theories about why broadcasters are losing adult viewers under 50: They're spreading out to cable, or watching shows online. Maybe network shows just aren't what they used to be.
CBS has another idea: Networks are winning fewer viewers 18-to-49 because there are fewer people 18-49. Not only that, the network says, but those who remain don't carry the weight they once did. They tend to skew younger, and to increasingly – gasp -- live at home, even up to the age of 34.
As CBS Corp. chief research officer David F. Poltrack puts it, in a dry bit of understatement: "This makes them of limited interest to a substantial number of advertisers."
Still, he says, CBS still understands "the whole youth culture thing." CBS, which has the oldest median viewer age, 56.1, won last season among 18-to-49-year-olds for the first time since 1991-92.
What's become of younger adult viewers is one of the biggest questions at the Television Critics Association summer press tour. So CBS gave Poltrack an entire panel Monday to make the case that 18-to-49-year-old viewers don't matter as much as they once did, and that networks and advertisers should broaden their focus beyond the one now considered most desirable.
Yes, it might seem self-serving for the oldest-skewing network to claim the influence of younger viewers is waning. But CBS is making the case while on top in the demo.
"This 18 to 49 demographic is a smaller percentage of the overall population in numbers. So why would anybody sell – this is what we tell advertisers – why would you want to continue to sell and focus your selling on a shrinking part of the total population?" Poltrack said to TheWrap.
CBS has long made the case that while its shows may not have the Twitter cache of cable hits, it is steadily delivering viewers. Its "NCIS," for example, is the most-watched scripted show on TV. ("The Walking Dead" is tops in the demo, edging out CBS's "The Big Bang Theory.")
"Don't assume that because 'NCIS' doesn't have a lot of people tweeting about it, that there aren't a lot of people talking about it," Poltrack said.
Poltrack says CNN's advertisers are increasingly looking for more specific audiences, such as men or women of a particular age. That goes against the conventional wisdom that advertisers want to target the youngest viewers possible so that they'll develop brand loyalty that will last years.
The network is trying to upend a tradition of advertisers seeking young viewers rather than older ones because older ones are easier to come by. Poltrack points to small but significant statistical changes that he says point to the declining influence of young adults.
People 18-49 now represent 55 percent of all adults, down from 62 percent a decade ago. (the number of adults 55 and older is up.) In the last year, 18-to-49-tear-olds have declined one percent since last year to 126,540 people.
Those young people are increasingly living in other people's homes. For many advertisers, they are less valuable than homeowners.
As of 2010, 82 percent of 18-to-24-year olds lived in someone else's home, up from 80 percent in 2000, according to the consulting firm Wilkofsky/Gruen Associates. Increasingly, people 25-34 are living in a similar situation: 56 percent of people in that age group now live in someone else's home, up from 54 percent in 2000.
Many of the 18-to-24-year-olds are living in a college dorm, but that's less likely to be the case with 25-to- 34-year olds.
"Probably the biggest chunk of that are people living with their parents," Wilkofsky/Gruen Associates president Arthur Gruen told TheWrap.
In a TCA panel Saturday, NBC entertainment chairman Bob Greenblatt took a more traditional view of why viewership is down among young adults, pointing to cable as one culprit.
"The decline year-to-year in broadcast television from 5 to 7 percent has been happening for the last two decades," he said. "So it isn't just a recent phenomenon, and it's been happening partly because cable is just taking viewers away."
The CW, meanwhile, has blamed its recent ratings woes in part on its core audience, people 18 to 34, increasingly watching TV online. CBS co-owns the network with Warner Bros. Entertainment.
CBS president Les Moonves made the case at TCA Monday that the internet isn't the enemy of broadcast TV – it's just part of broadening its platforms from TV to other devices. He noted that CBS's "Under the Dome" earned roughly 13.5 million viewers initially, but ticked up over 20 million including DVR and streaming audiences.
"Since I've been in the network television business, which is over 30 years, people have been saying, 'Oh, the model is dead.' The model's never been dead. It's just evolving. It's changing," he said.