Critics last summer fired angry barbs at ABC Entertainment president Ted Harbert when he was the first to publicly admit that the networks were aiming to eliminate main-title sequences and, therefore, the theme songs that many viewers so fondly remember.

A recent survey of primetime programming on all four networks, however, shows that NBC has far exceeded its competitors in cutting back main-title sequences and even more obviously, in eliminating the traditional end-credit sequence from the airwaves.

Some 30% of all entertainment shows on NBC now superimpose their opening credits over the teaser, compared to 22% on CBS, 20% on ABC and 14% on Fox. End-credit rolls on NBC are now uniformly handled in a split-screen manner, with additional program material, outtakes or promos for upcoming shows sharing the screen.

CBS and Fox have adopted the split-screen concept in some cases, usually near the end of the evening's programming, while ABC opts for more program material beneath full-screen end-credit sequences.

Time allotted to both main- and end-title sequences has also been substantially reduced. Full main-title sequences on NBC average 45 to 50 seconds; on ABC, from 30 seconds to a minute; CBS, 45 to 50 seconds; Fox, 30 to 50 seconds. End-credit rolls vary, especially if they run over more program content. But as a rule they are far shorter than in past years: NBC, CBS and ABC average about 35 seconds while Fox continues somewhat longer at an average of 40 seconds.