‘NCIS’ goes big, helps spinoff

NCIS, ratings leader
Rocky Carroll, left, and Mark Harmon in an episode of ‘NCIS’ that aired Tuesday. (Cliff Lipson/CBS)

Mark Harmon continued as king of the Tuesday ratings and helped an “NCIS” spinoff with a two-part story.

The original “NCIS” averaged 15.1 million viewers for a story that concluded on “NCIS: New Orleans” with 10.2 million viewers. The Scott Bakula spinoff had its biggest audience since Dec. 13.

“Bull,” with former “NCIS” star Michael Weatherly, aired between the two dramas and pulled in 10.6 million.

NBC had reason to crow that “This Is Us,” its freshman drama, was the No. 1 show nationally with…