• by Wayne Friedman , January 25, 2007

Fox's typical fourth-quarter rating swoon came with some unusual and disconcerting news: The network's median age for viewers is now five years older.

According to new Nielsen data, Fox median age is now 42 years old, moving up from 37 in the fourth-quarter 2005. Networks tend to become slightly older or younger by one year or so. But rarely has a network witnessed a spike like Fox's this past fall.

"What happened was that they dropped their young comedies and went to older-skewing dramas," says Lyle Schwartz, senior vice president and media research director for Mediaedge:cia.

"Five years is significant," adds Schwartz. "I don't recall any jump being that large. Usually, it's a year or two."

Still, analysts don't necessarily think this is all that bad. Brad Adgate, senior vice president and corporate media director for Horizon Media, says Fox's median age will still be lower than ABC, CBS and NBC.

This revelation probably won't have much effect on Fox's bid for the most valuable 18-49 viewing title. That still depends on how its heavyweight "American Idol" franchise performs--as well as other shows.

"As long as they have "American Idol," "24," "House" and the Sunday night comedies, they'll probably win again," adds Adgate.

"They'll just skew to the older side of the 18-49 demo now," says Schwartz.

While Fox has been in the thick of battle for the 18-49 title for the last several years, it has easily been tops among 18-34 viewers--an area that new network CW says is its target.

The CW was the only network to have a median age under 40 in the fourth quarter, with 32. For the entire season in 2005-2006, its network predecessors--WB and UPN--were 36.6 and 31.1, respectively.

While Fox had a 37 median age in the fourth quarter of 2005, for the season overall, it was 40.4. If the trend continues, Fox's median age of 42 might climb a bit by year's end.

For the fourth quarter, ABC's median age was 47--up one year from the same period a year ago. CBS remained the same at 52. Only NBC improved--dropping two years, from 49 to 47. Much of this has to do with its new show "Heroes," which has a median age of around 40.