ABC’s “American Inventor” had a strong first two weeks, dominating weaker-than-usual competition. But with NCAA basketball over and “CSI” back on Thursday night, the ABC reality show fell off sharply in its third outing last night.
 
“Inventor” posted a 3.7 overnight rating among viewers 18-49 in the 9 p.m. timeslot last night, down 30 percent from the 5.3 it averaged over its first two episodes, when it was up against CBS’s men’s basketball tournament coverage.
 
No one would have expected “Inventor’s” ratings to stay where they were before TV’s No. 1 crime drama returned from its mini-hiatus, but a 30 percent dropoff is not good news for ABC, which plans to move “Commander in Chief” to Thursday nights in two weeks to lead out of “Inventor.”

ABC is still better off than it was a few months ago, when it rarely rose above a 3.0 in the timeslot.
 
And “Inventor” did manage to deflate the return of “CSI.” The Vegas-set procedural posted a 7.9 among 18-49s last night, down 13 percent from the 9.1 it had averaged over its last four original episodes. That 7.9 was 68 percent better than the 4.7 CBS averaged in the slot the past two weeks with NCAA basketball.
 
“Inventor” was third in it timeslot last night among 18-49s, behind “CSI” and NBC’s comedies “My Name is Earl” and “The Office,” which it finished ahead of in its first two outings.

“CSI,” the night’s top-rated show in the demo, helped CBS finish first for the night among 18-49s with a 6.5 average rating and a 17 share. NBC was second at 4.5/12, ABC third at 2.9/8, Fox fourth at 2.4/6, WB fifth at 1.7/5, Univision sixth at 1.7/4 and UPN seventh at 0.8/2.
 
CBS led or tied for the lead during each hour last night, beginning with a 5.9 rating at 8 p.m. for “Survivor.” NBC was second that hour with a 3.5 for “Will & Grace” (3.6) and a repeat of “Earl” (3.4), with ABC’s “Extreme Makeover: Home Edition” and Fox’s repeat of “That ‘70s Show” (2.4) and a new episode of “The Loop” (2.0) tied for third at 2.2. WB was fifth with a 1.9 for “Smallville,” Univision sixth with a 1.5 for “Barrera de Amor” and UPN seventh with a 0.9 for repeats of “Everybody Hates Chris” and “Love, Inc.”
 
At 9 p.m. CBS led easily with its 7.9 for “CSI,” followed by a 4.3 for NBC for “Earl” (4.4) and “The Office” (4.1). ABC was third with its 3.7 for “Inventor,” Fox fourth with a 2.6 for “The O.C.,” Univision fifth with a 2.0 for “Alborada,” WB sixth with a 1.5 for “Supernatural” and UPN seventh with a 0.7 for repeats of “Eve” and “Cuts.”
 
At 10 p.m. CBS and NBC tied for the lead at 5.6, CBS for “Without a Trace” and NBC for “ER.” ABC was third that hour with a 2.7 for “Primetime” and Univision fourth with a 1.4 for “Aqui y Ahora.”
 
CBS easily led the night among households with a 12.6 average rating and a 20 share. NBC was second at 6.8/11, ABC third at 5.1/8, Fox fourth at 3.3/5, WB fifth at 2.5/4, Univision sixth at 1.9/3 and UPN seventh at 1.5/2.