It looks like NBC should have stuck with Conan, after all. Three weeks into the first fall season since he rejoined the "Tonight Show" in March, Jay Leno — late night's top dog since 1995 — is increasingly losing his lead against "The Late Show With David Letterman."
More importantly, he's scoring lower numbers in the key adults 18-49 demographic than Conan O'Brien did during his brief "Tonight Show" run.
This summer, from the week beginning May 31 to the week that ended Sept. 19, Leno had an average audience of 3.83 million total viewers and a 1.0 rating in the key demo.
His summer numbers this year were good enough to beat Letterman, who averaged 3.03 million viewers and a 0.8 rating during the same period. Leno also improved on Conan's average audience in summer 2009 by roughly 10 percent.
But Leno was down substantially from his most recent summer on the air in 2008, when he averaged over 4.5 million total viewers. And though he beat O'Brien in viewers, he was down 30 percent from Conan's summer 2009 average 1.3 rating in the key demo.
And things haven't gotten any better for Leno with the start of the fall season, which began the week of Sept. 20. In the first full three weeks since then, Leno has averaged 3.75 million total viewers — down 2.1 percent* from his summer numbers and a 1.0 in the key demographic, a 10 percent drop from O'Brien's numbers in the demo during the same time last year.
With Leno's slipping ratings, Letterman has made significant gains against the "Tonight Show" this fall. So far this season, Letterman's "Late Show" has grown its summer numbers by 19 to an average audience of 3.62 million total viewers, closing the gap between the two programs by 83 percent.
Over the summer, Leno had over 800,000 more average total viewers than Letterman, but so far this fall, the "Tonight Show" is only beating the "Late Show" by an average of 130,000 total viewers. Letterman has also gained on Leno in the key demo this fall.
During the summer, Letterman averaged a rating of 0.8 among adults 18-49 compared to Leno's 1.0. This fall, Letterman closed that gap by 10 percent by bringing up his average 18-49 rating to 0.9.
For the week ending Oct. 8, "The Late Show" tied the "Tonight Show" in the key demo for the first time this season. If these trends continue, Letterman may soon pull out in front of Leno for the first time in 15 years.
Either way, a new era is about to begin in late night TV, when O'Brien's new TBS show debuts on Nov. 8.
*Update: Though the correct numbers were given for total audiences an earlier version of this post incorrectly omitted a decimal point and referred to Jay Leno’s fall numbers as being down 21 percent from his summer ratings rather than 2.1 percent.