“The real issue is: by paying for interviews, are you changing the news?” said David Westin, who was the president of ABC News until last winter, when many licensing deals were done. The economic tradeoff rarely makes sense, Mr. Westin said, in a time of budget and staff cuts at network news divisions.

“If you could prove that by spending $20,000 you would make $70,000, O.K., I can justify that,” Mr. Westin said. “But I’ll be doggone if you could go through any of those payments, trace them through and see if it made any sense.”

The Poynter Institute, the journalism ethics group, said last week that the payments corrupted journalism. The group suggested that the trend could be reversed if networks would agree to pay license fees only to people not involved in the story, like eyewitnesses who happen to record a news event.

The practice of paying for interviews is common in Britain. In the United States, magazines like Us Weekly pay for wedding and baby photographs of celebrities and are often granted interviews at the same time, and tabloid shows like “TMZ” and “The Insider” pay for stories and interviews. But they are generally not held to the same standards as the network news divisions, all of which have ethics policies against paying for interviews.

So the networks pay for photos, videos, hotel rooms — even special events, as NBC did in 2007, when its entertainment division paid an estimated $2.5 million for the rights to the “Concert for Diana,” putting its news division in line for exclusive interviews with Prince William and Prince Harry.

Some news executives said that the subjects of interviews were learning how much their stories were worth. “Money is being asked for more and more of the time,” said Jeff Fager, the chairman of CBS News, who denounced the practice. “If you’re in the business of having to pay people to get a story, it can’t be worth it,” he said.