Katie Couric was a hit as "CBS Evening News" anchor -- at least on the first night.

The ratings for her initial broadcast Tuesday were 86 percent above what CBS averaged on the same day last year, according to a preliminary measurement of the nation's 55 biggest markets by Nielsen Media Research.

CBS had a 9.1 rating and 17 share in those markets, compared to the 5.7 rating and 11 share for ABC's "World News" and 5.3 rating and 10 share for NBC's "Nightly News," Nielsen said. A ratings point represents 1,102,000 households, or 1 percent of the nation's estimated 110.2 million TV homes. The share is the percentage of in-use televisions tuned to a given show.

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Typically, NBC leads in the evening new ratings, with ABC second and CBS last. All the networks expected extra curious viewers to watch Couric's debut.

Couric seemed to siphon viewers most from her old network: NBC was down 23 percent from a year ago and ABC was down 15 percent, Nielsen said. More complete ratings from the entire country were due later Wednesday.

"This exceeded our expectations," said David Poltrack, chief researcher at CBS.

Couric showed she wasn't afraid to take chances on her first night. She opened with a flashy investigative report, interviewed an expert on the set and allowed an outsider to deliver his own commentary. None of that would be commonplace in a news format she has called formulaic and in need of spicing up.

"We're trying a few new things here on the evening news," Couric said.

The most obvious was her presence as the top female in network news. She was introduced in a voiceover recorded by CBS News legend Walter Cronkite, but her newscast looked nothing like the sober recitation of news headlines common in Cronkite's era.

Couric's long-awaited debut capped a tumultuous period for the evening news. For more than two decades, the network news was dominated by Tom Brokaw, Peter Jennings and Dan Rather. Now, Couric will compete against Brian Williams at top-rated NBC and Charles Gibson at ABC.

She arrived at CBS after 15 years as host of NBC's "Today" show, where she was accustomed to always being first in the ratings. The "CBS Evening News" is third, but Couric has said that status could be liberating.

On a relatively slow news day, CBS opened with chief foreign correspondent Lara Logan being escorted by a Taliban commander to view soldiers displaying their weapons less than 10 miles from a U.S. base.

Logan, dressed in black with only part of her face visible, was heard asking one of her guides, "Am I allowed to smile?"

Following a conventional report on President Bush's speech about the terrorist threat, Couric showed her "Today" roots by bringing New York Times columnist Thomas Friedman into the studio for a discussion on the terrorist threat.

"Things seemed to be going well in Afghanistan," she said. "What happened? Why is it unraveling now?"

She then whipped through a handful of headlines -- a corporate turnover at Ford, mourning over the killed "crocodile hunter" -- all before the first commercial.

Couric also introduced "Free Speech," a segment that will periodically feature outsiders giving a brief commentary. Morgan Spurlock, who subsisted on McDonald's for 30 days in his documentary "Supersize Me," was first up, talking about how the nation's political divide is exaggerated by the media. Couric promised that Rush Limbaugh would be featured Thursday.

The rest of the broadcast was dominated by longer features on the discovery of a new oil reserve in the Gulf of Mexico and high school students who draw portraits of poor orphans across the world. Couric also showed the first pictures of Tom Cruise and Katie Holmes' new baby, Suri.

She made only one slip, mispronouncing "soil" as "sole" at one point but quickly correcting herself.

"I felt the show, taken as a whole, had too much softness to it," said Bob Zelnick, a former ABC News correspondent and current Boston University journalism professor. He said, however, that Couric won't really be judged until the public sees her perform when big news breaks.

Couric's only real nod to her newbie status came at the end, with a joking report on her difficulties coming up with a signoff. She showed clips of Cronkite, Chet Huntley, Dan Rather, and even fictitious anchormen Ted Baxter and Ron Burgundy giving their final words, then invited viewers to submit suggestions on the CBS News Web site.

"Thank you so much for watching," she said, "and I hope to see you tomorrow night."

As the end credits rolled, Couric, wearing a white jacket over a black shirt and skirt, was leaning against the edge of her desk, showing her famous legs.

She gulped a celebratory martini handed to her when the cameras turned off, according to CBSNews.com.

She's the first woman hired to anchor one of the three network nightly newscasts on her own. Predecessors Barbara Walters, Connie Chung and Elizabeth Vargas only got their jobs in partnership with men.

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