CBS expects to regain its lead in the network prime-time ratings by early 1978, John Schneider, president of the CBS/Broadcast Group told Wall Street analysts today.

CBS, which was the leader in the prime-time television ratings wars for the last 20 years, began the season in an unaccustomed third position and only last week moved ahead of NBC for the No. 2 spot, with ABC holding a commanding lead for first place.

We will not be in first place this year or in the fall of 1977," Schneider said, noting that "the momentum of ABC is such that it would be hard to catch by this fall. But I believe we have a chance to regain first place early in 1978. That is our goal."

CBS, Inc., president John D. Backe, in his first appearance before securities analysts since he took over his post last October after the surprise ouster of Arthur Taylor, tried to stress his networks continuing lead in overall television viewing while glossing over its problems in prime time. He also said the network is "filing up the pipeline" of programming and expects it to be full "in mid-summer and fall."

Backe predicted that network telivision advertising expenditures will increase about 12 per cent in 1977, half of last year's spectacular gain, with national spot and local ad spending rising 15 per cent.

Backe said he had no reason to believe that CBS chairman William S. Paley would not step down as the company's chef executive officer in May, as Paley had earlier indicated, and noted that the chairman had increasingly been giving him responsibilities in recent months. But he added that he was not certain who Paley would name to succeed him as chief executive officer.

Backe and other officials, in their summary of the current state of the company - which also includes record, publishing and leisure division - said:

The domestic share of the CBS/Records Group - primarily the Columbia and Epic labels - increased 1 or 2 per cent in 1976, probably at the expense of arch competitor Warner Communications' WEA subsidiary.

Television programming costs in the last year have risen from $120,000 for a typical half-hour comedy show to $130,000, and from $250,000 for an hour show to $270,000. But CBS believes it has leeway to control overall costs and maintain a profit margin by putting a lid on more expensive specials programming.