ABC's Evening News Bests NBC in Coveted Age Group ABC's evening newscast, "World News With Diane Sawyer," bested the longtime leader, "NBC Nightly News With Brian Williams," among 25- to 54-year-old viewers last week, ending a nearly five-year streak by NBC and renewing interest in the once-predictable ratings race. "NBC Nightly News" remained No. 1 among total viewers, which is traditionally the bragging rights category in television. But ABC's win is significant because television ads on news programs are bought and sold based on the coveted age group of 25- to 54-year-olds. Ms. Sawyer has been seeking to snap Mr. Williams's streak in that category for years. For ABC, it was a narrow victory: just 38,000 viewers ages 25 to 54 separated the two shows. Partly for that reason, people at NBC News cautioned that ABC's evening show victory could be a one-time aberration. Last spring and summer, though, those same people saw their prized morning show "Today" fall to second place behind ABC's "Good Morning America," first in total viewers and then in the 25- to 54-year-old demographic. The "G.M.A." streak is now nearly one year old. As is the custom in these bitterly contested ratings competitions, NBC's news release about the ratings made no mention of ABC's gains; it simply excluded the 25- to 54-year-old viewership totals and emphasized that "Nightly News" had been winning among total viewers for years. "We are grateful for another consecutive win in total viewers and are focused on producing the best newscast for our audience," an NBC News spokeswoman said Tuesday morning. Among total viewers, "Nightly News," which had an average of 7.54 million viewers last week, beat "World News" by about a quarter of a million. Among viewers ages 25 to 54, "Nightly" had about 1.88 million, 38,000 fewer than "World News." ABC said this was its first win since the week of Nov. 17, 2008, shortly after the election of President Obama. In a statement, the executive producer of "World News," Michael Corn, said he and Ms. Sawyer appreciated the support from ABC stations "and most of all the loyal viewers who trust us to bring them the most important and compelling stories of the day." Mr. Corn added, "We have a lot more work to do. We're just getting started. Internally, the ABC News president, Ben Sherwood, has encouraged the program staff to aim for first place both in the 25- to 54-year-old demographic and in the category of total viewers. The victory is shared between Ms. Sawyer, who has been the anchor of "World News" since 2009, and David Muir, one of her principal fill-ins. Last week Ms. Sawyer anchored on Monday and Tuesday while Mr. Muir anchored the rest of the week. According to the daily Nielsen ratings, ABC lost to NBC, slightly, on the days Ms. Sawyer anchored but beat NBC on the days Mr. Muir sat in. ABC played down that aspect, though, and in a Twitter message on Tuesday Mr. Sherwood called Ms. Sawyer the program's "captain." Mr. Muir and another ABC anchor, George Stephanopoulos, are widely seen within the television industry as the two possible successors to Ms. Sawyer. Ratings for the old-fashioned nightly newscasts on NBC, ABC and CBS have been relatively steady for the last couple of years, after decades of slow and steady erosion because of competition on television and, most recently, on the Internet. About 22.1 million people watched one of the three programs on an average weeknight in 2012, down 2 percent from an unusually strong 2011. "Despite those losses, the network evening news is still a popular news source," Pew Research Center wrote in its annual State of the News Media report. In 2012, for example, more than four times as many people watched the three network evening newscasts on ABC, CBS and NBC than watched the highest-rated shows on the three cable news channels (CNN, Fox News and MSNBC) during prime time. This year ABC's "World News" and the third-place "CBS Evening News" have shown some momentum at the expense of "NBC Nightly News," which Mr. Williams has anchored since 2004.