The formula is simple: Take a high-minded topic and a few knowledgeable talking heads, and rent a hall. Then get a sponsor willing to shell out top dollar to splash its name on the ensuing discussion.

To give the event an extra sheen of authority and credibility, it helps if the organizer is a prestigious news organization.

For the news media, it’s no longer enough to merely report the day’s events. At a time when traditional advertising revenue is under stress, news organizations are developing a lucrative — and sometimes controversial — sideline by orchestrating live discussions about events and ideas in the news.

The Washington Post, Politico, National Journal, the New York Times and NPR, among many others, have plunged into the business of hosting conferences and panels about such weighty topics as health-care reform, climate change and income inequality. The field has become so crowded that one wit jokes that she can eat a free breakfast every day in Washington just by showing up to one of the town’s many media-run panel discussions.

Politico staged about 100 such events last year. The Post held 26 events, from a forum on preventing childhood obesity to another on cybersecurity. The Atlantic, an early organizer, orchestrates dozens of discussions large and small; among its events is the sprawling Aspen Ideas Festival and “salon”-style dinners that bring journalists, newsmakers and corporate sponsors together.

The events are a perfect match between revenue-hungry media outlets and the business interests that want to put their names in front of select audiences, typically no more than a few hundred people. The companies pay fees — sometimes as much as six figures for big events — to sponsor events that draw lobbyists, policy experts, government officials, journalists and mere civilians. The sponsors get their names plastered around the meeting hall and, usually, an opportunity for a representative to make introductory remarks to the audience.

While news organizations, including The Post, won’t discuss specific financial details, event-hosting appears to be a growth business. The Atlantic earned about 20 percent of its revenue from event sponsorships last year, according to Elizabeth Baker Keffer, the outgoing head of the magazine’s 30-person events division. In a recent staff memo, her boss, Atlantic Media Chairman David Bradley, said the Atlantic’s sister publication, the National Journal, generated about two-thirds of its revenue from event sponsorships and digital advertising.

Critics contend that the traditional separation between editorial content and advertising is eroded when news organizations create single-issue discussions financed by a sponsor with a vested interest in the topic.

“Sponsoring an event is like sponsoring a particular news article,” says David Halperin, a lawyer, writer and advocate for environmental and education groups.

Halperin adds, “If Exxon gives you $100,000 to do an event, your moderator isn’t likely to mercilessly attack Exxon.”

In Washington, the sponsor market tends to be dominated by large corporations and their trade associations. Defense contractors Northrop Grumman and General Dynamics, for example, were among the sponsors of Atlantic Media’s invitation-only Defense One Summit in November that featured Secretary of Defense Chuck Hagel and the acting secretary of the Air Force.

The coal-industry group, the American Coalition for Clean Coal Electricity, recently sponsored two panels on energy policy. AARP was one of three sponsors of The Post’s three-city series on caregiving.

“Corporate interests do get a special kind of exposure” through these sponsorships, says Peter Hart, a director of the media watchdog group Fairness and Accuracy in Reporting.

Journalists say they — not their business colleagues — select the topics, questions and panelists for their discussion panels, a step designed to ensure editorial integrity.

But the lines between a news organization’s editorial and business sides aren’t always brightly drawn, as in the case of a 2012 panel organized by the publication Chronicle of Higher Education. Without mentioning it in its pre-event promotions, the publication allowed Career Education Corp., a for-profit college operator, and the nonprofit trade group Education Finance Council to select the panelists for a discussion about ways to reduce student defaults on college loans. The panel was moderated by Jeff Selingo, a former top editor at the Chronicle; at the time, Selingo held the title of editor-at-large, although he reported directly to the company’s chief executive, according to Michelle Thompson, the Chronicle’s associate publisher.

Thompson acknowledges that the Chronicle should have alerted readers and possible attendees upfront that the panel was a “live advertorial” — the equivalent of a special advertising section tucked within the pages of a print publication. She says the Chronicle ultimately telephoned registrants to disclose the nature of the arrangement and is being more careful to make sure that the terms of “live advertorials” organized by the business side are fully disclosed beforehand. Thompson said editors and reporters have sole control over topics and participants when events are newsroom-driven.

Politico Pro’s forum on federal agriculture policy in November seemed to suffer from diversity issues.

The event was sponsored by Fuels America, an industry coalition that favors increased use of biofuels, including corn-based ethanol. The keynote speaker was Agriculture Secretary Tom Vilsack, the former Democratic governor of corn-intensive Iowa. A later panel included the head of the Corn Refiners Association; Rep. Steve King (R), also of Iowa; the director of biofuels for DuPont, a Fuels America member; the public-policy director for the American Farm Bureau, which backs expanded biofuel development; and the president of the Minnesota Farmers Union, whose national organization is another Fuels America member.

There were no representatives of environmental, scientific, farm-labor or fossil-fuel groups; the only potentially anti-corn voice was Rep. Jim McGovern (D-Mass.), the co-chairman of the House Hunger Caucus.

Politico’s editor, John Harris, defended the agriculture panel, saying, “We had a Republican and Democratic member of Congress who came from strongly opposing views on agriculture policy, and in addition to that, we had the president of the Minnesota Farmers Union, who is often in opposition to corporate farm interests.”

The Post’s executive editor, Martin Baron, said his newspaper requires “multiple sponsors” for its events “for the purpose of signaling that we welcome, and will include, various points of view” in any discussion, all of which are streamed live and open to the public. The paper’s editorial staff, which directs the events, has rejected sponsors’ ideas for topics before — and has rejected would-be sponsors, too — although Baron declined to cite specific instances.

The Post’s caution is born of bitter experience. In 2009, in its first foray into sponsored conference and events, former members of its business staff proposed hosting private, off-the-record “salons” at publisher Katharine Weymouth’s house. The idea was to engage business leaders, government officials and some of the newspaper’s journalists in a series of exclusive discussions that would attract a sponsor willing to pay a proposed six-figure price tag, according to a flier promoting the event.

When word of the proposal leaked, it was roundly denounced as an effort to sell access to important Washington players. The Post immediately dropped the idea.

But that hasn’t stopped other publications from using their brand names to draw sponsors and newsmakers to events that are closed to the public.

Forbes magazine convenes groups of up to two dozen “thought leaders” to discuss health care, luxury goods, philanthropy and other topics each year. The sessions are sponsored and off the record, meaning that Forbes doesn’t report what’s said.

The Atlantic organizes a series of invitation-only dinners in which about 25 experts and journalists discuss a topic, all of it underwritten by a sponsor. Some of the discussions — such as a recent one in Miami about entre­pre­neur­ship, sponsored by Bank of America — are “on background,” meaning that reporters can’t attribute what’s said to a specific individual (the magazine leaves it up to its business staff to determine whether an event is on the record or on background).

The Atlantic says its dinners differ from The Post’s salons because the magazine doesn’t invite government officials and because the “on background” ground rules enable at least some reporting of the event.

“It is our position that holding select events on background can facilitate a more reasoned debate of contentious issues by enabling participants to go beyond mere sound bites and position-taking,” says Emily Lenzner, a spokeswoman for the magazine.

But the on-background edict leaves the Atlantic’s reporters handcuffed: Under the rules, not even they can report who said what at an event organized by their magazine.