Fast National ratings for Thursday, January 26, 2012.

CBS' "The Big Bang" theory followed up on last week's slim victory over "American Idol" among young viewers by expanding that advantage and even topping FOX's slightly wounded juggernaut overall. Of course, "Idol" crushed the still-solid "Rob" and, aided by a bump for "The Finder," led FOX to Thursday wins.
Among adults 18-49, FOX averaged a 4.1 rating, easily beating CBS' 2.8 rating in the key demographic. NBC's 1.4 rating and the 1.2 rating for ABC followed, while The CW aired a movie for a 0.5 key demo rating.
Overall, FOX averaged an estimated 12.75 million viewers for Thursday primetime along with a 7.6 rating/12. CBS was a respectable second with a 7.0/11 and 11.27 million viewers, far ahead of ABC's 2.5/4 and 3.88 million viewers and NBC's 2.4/4 and 3.65 million viewers. The CW averaged 1.31 million viewers and a 0.9/1.
[Univision averaged 3.75 million viewers and a 1.6 rating among adults 18-49 for Thursday primetime.]
8 p.m. - FOX's "American Idol" averaged 16.99 million viewers and a 5.4 rating among adults 18-49 to win the 8 p.m. hour, but there were dynamic splits between the first half-hour (15.46 million and a 4.8 key demo) and the second half-hour (18.53 million and a 6.0 key demo). The cause of that split had something to do with "The Big Bang Theory" averaging 15.96 million viewers and a 5.4 key demo rating for the 8 p.m. half-hour, while "Rob" averaged 11.58 million viewers and a 3.5 key demo rating. ABC's repeat of "Wipeout" averaged 4.86 million viewers for third and a 1.5 key demo rating for fourth. NBC was fourth overall and third in the key demo with low weeks for "30 Rock" (3.84 million viewers and a 1.6 key demo) and "Parks and Recreation" (3.48 million and a 1.7 key demo). The CW's airing of "The Covenant" averaged 1.35 million viewers and a 0.5 key demo rating.
9 p.m. - A repeat of "Person of Interest" put CBS into first overall for the 9 p.m. hour with 10.48 million viewers and finished second with a 2.1 key demo rating. FOX's "The Finder" capitalized on lack of original drama content in the hour to take a big leap to 8.51 million viewers and a 2.9 rating among adults 18-49. ABC's repeat of "Grey's Anatomy" averaged 3.99 million viewers for third and a 1.3 key demo rating for fourth. NBC's "30 Rock" (4 million and a 1.9 key demo) and an "Up All Night" repeat (3.03 million and a 1.4 key demo) were fourth overall and third in the demo. The CW's "The Covenant" averaged 1.27 million viewers and a 0.5 key demo rating.
10 p.m. - CBS closed primetime in first with 9.56 million viewers and a 1.9 rating among adults 18-49 for a "Mentalist" repeat. NBC's new episode of "The Firm" was up from last week, though "up" means 3.77 million viewers and a 1.0 key demo rating. ABC's "Private Practice" averaged 2.79 million viewers and a 0.9 key demo rating.
All ratings information comes from preliminary Fast National Nielsen data, which includes live and same-day DVR viewing. All numbers are subject to change.
A long-time member of the TCA Board and a longer-time blogger of "American Idol," Dan Fienberg writes about TV, except for when he writes about movies or sometimes writes about the Red Sox. But never music. He would sound stupid talking about music.