COSBY SHOW AGAIN TOPS IN RATINGS

Although Sunday’s opening segment of CBS’ “The Atlanta Child Murders� was preceded by controversy and considerable publicity, it didn’t top the ratings. But it did win its time period and was the nation’s 12th most-watched program last week.

“The Cosby Show,� Bill Cosby’s NBC situation comedy about a black family, was the week’s highest-rated prime-time program for the second week in a row. It was seen in nearly 22.2 million homes, according to A. C. Nielsen Co. figures released Tuesday.

The two-hour first chapter of “Murders,� which concluded Tuesday night, was seen in nearly 18 million homes. Its closest network competition Sunday night was NBC’s TV movie comedy, “Poison Ivy,� seen in 16.8 million homes.

ABC’s competing TV movie, “Surviving,� a drama about teen-age suicide, was third in the Sunday night ratings race. “Surviving� was seen in an estimated 15.4 million homes, according to the Nielsen figures, which did not bring good news for ABC.

The network, third in ratings this season but trying to make a strong showing in the February ratings sweeps period, declined to join CBS and NBC last Wednesday in airing the Democratic Party’s response to President Reagan’s State of the Union message, which all three networks carried simultaneously.

ABC instead aired its regularly scheduled “Dynasty,� which the majority of viewers preferred to the Democratic response. “Dynasty� wound up as the week’s second highest-rated program, seen in nearly 22.2 million homes.

(ABC aired the Democratic reply on Thursday night. No ratings are available for that because the broadcast was “sustaining,� or unsponsored. Both CBS’ and NBC’s telecast of the Democrats’ program also were unrated.)

ABC’s action wasn’t enough to help the network escape third place in last week’s ratings. The Nielsen figures show that NBC came in first with an 18.2 rating average, its shows seen in an average of nearly 15.5 million homes, followed by CBS (17.0 rating), whose programs were seen in 14.4 million homes.

ABC had an average prime-time rating for the week of 16.6, or nearly 14.1 million homes.