The Leno Effect: NBC drops in three time slots

While "The Jay Leno Show" has performed well since the start of the season, NBC's 10 p.m. slot is down significantly compared with last year -- as are the broadcaster's local news telecasts and "The Tonight Show."

When isolated, "Leno Show" is pulling better-than-expected numbers at 10 p.m. The show has demonstrated that with a strong lead-in, it can retain a significant share of viewers and post a competitive number. Also, Leno has decreased the amount of time-shifting at 10 p.m., according to preliminary estimates released by TiVo, meaning more viewers are watching the hour live -- something advertisers and networks vastly prefer.

But while the media has largely focused on Leno's overnight numbers, NBC's 10 p.m. and late night shake-up impacted a trio of time periods (more if you count late-late night) and it's worth checking how those slots are performing.

Since the start of the season compared to the same period last year* ... 

>> NBC has averaged a 2.0 adult demo rating at 10 p.m. -- down 43%. (Last year the network aired programs such as the latter half of a "Heroes" premiere, "Law & Order: SVU," "Lipstick Jungle" and "ER" in the slot).

>>  From 11 p.m. to 11:30 p.m., when affiliates air local news, NBC stations averaged 6.4 million viewers -- down 16%. 

>> "Tonight Show With Conan O'Brien" averaged a 1.0 adult demo rating, down 23% compared with last fall when Leno ran the program.

NBC is not alone in some of these drops. ABC has scripted programming and is also down double digits at 10 p.m., with last night's "The Forgotten" scoring a lower rating than "Leno." ABC is likewise down 13% at 11 p.m.. CBS posted slight 11 p.m. declines as well.

The Leno ratings story boilerplate: Debating The Leno Effect remains about context and big pictures -- and there's always greater context and a larger picture to be found by adding one more statistic, or waiting for one more day of data. Leno in primetime is NBC's year-round strategy, and pulling numbers at this point cannot tell the full tale.

* Did not include Friday since a presidential debate skewed the time period last year and "Tonight Show" aired a repeat this year due to Conan's injury ...