Fast National ratings for Thursday, December 8, 2011.
 
Led by "The Big Bang Theory," "Person of Interest" and "The Mentalist," CBS swept the primetime hours both overall and in the all-important demographic. The only half-hour CBS didn't control was 8:30, when FOX's "X Factor" results snuck in to nip "Rules of Engagement."
 
The returns were less impressive for a slew of winter-themed offerings on ABC, nor for NBC's Thursday night test for "Grimm" and the last new episode of "Community" for the foreseeable future.
 
[Note: Both FOX and CBS had NFL preemptions due to the Cleveland-Pittsburgh  Thursday night game. Expect numbers for both networks to tick down slightly when final figures come in, though it's unlikely the changes will be enough to impact positions for the night.]
 
Among adults 18-49, CBS averaged a 3.3 rating in primetime, beating out FOX's 2.8 rating for first in the key demographic. NBC averaged a 1.9 rating for third, beating ABC's 1.7 rating. The CW's repeats averaged a 0.4 key demo rating.
 
Overall, CBS averaged an estimated 13.29 million viewers for the night along with an 8.3 rating/13 share. FOX was second with a 5.7/9 and 9.47 million viewers, far ahead of the 3.5/6 and 5.965 million viewers for ABC. With a 2.6/4 and 4.23 million viewers, NBC was fourth overall. The CW averaged 1.06 million viewers and a 0.7/1.
 
[Univision averaged 3.245 million viewers and a 1.4 rating among adults 18-49 for Thursday night.]
 
8 p.m. - CBS started primetime in first with "The Big Bang Theory" (14.42 million viewers and a 4.7 key demo rating) and "Rules of Engagement" (10.96 million viewers and a 3.2 key demo rating). Another chaotic results episode for "The X Factor" averaged 9.94 million viewers and a 3.0 rating among adults 18-49 for FOX, with numbers predictably taking a big jump at the half-hour. ABC's "Winter Wipeout: Deck the Balls" special averaged 6.63 million viewers and a 1.9 key demo rating in third. On NBC, "Community" (3.62 million and a 1.5 key demo rating) and "Parks & Recreation" (3.66 million and a 1.7 key demo), were both down a hair from last week, when they faced CBS repeats. The CW's "Vampire Diaries" repeat averaged 1.245 million viewers.
 
9 p.m. - "Person of Interest" had a strong night (remember the football warning) with 13.43 million viewers and a 3.0 rating among adults 18-49 for CBS. FOX's "Bones" averaged 9.005 million viewers and a 2.7 key demo rating in second. ABC's Christmas-tinted "America's Funniest Home Videos" averaged 6.485 million viewers and a 1.9 key demo rating for third overall and fourth in the demo. NBC's "The Office" (5.8 million viewers and a 2.9 key demo) and "Whitney" (4.14 million viewers and a 1.9 key demo) were flat from last week. On The CW, a "Secret Circle" repeat drew 873,000 viewers.
 
10 p.m. - CBS' "The Mentalist" closed primetime in first with 13.75 million viewers and a 3.0 rating among adults 18-49. ABC's "The Great Big American Auction" averaged 4.78 million viewers and a 1.4 key demo rating. NBC's special Thursday airing of "Grimm" averaged 4.095 million viewers and a 1.6 key demo rating, down in viewers, but up in the key demo from last week's new "Prime Suspect."
 
 
All ratings information comes from preliminary Fast National Nielsen data, which includes live and same-day DVR viewing. All numbers are subject to change, particularly in the case of live events.