Academic research and anecdotal evidence show that “freewheeling brainstorming sessions” do little if anything to generate ideas, according to a business school professor, The Wall Street Journal reported.

“You do not get your best ideas out of these … sessions,” Sheena Iyengar, a professor at Columbia Business School, told the Journal. “You will do your best creative work by yourself.”

Iyenger came to the conclusion that group brainstorming is usually a waste of time in her new book, Thing Bigger, in which she combined academic research and interviews with more than a thousand people.

Problems with brainstorming include nonstop talkers with mediocre suggestions and brilliant people who don’t speak up, Iyengar found. She also argues that the rule of reserving judgment and building on what others say does not work when making business decisions.

“I’ve gone from being the biggest brainstorming proponent to feeling anxiety if a meeting doesn’t have a clear agenda,” Drew Himel, chief executive of Fireside, an e-commerce strategy firm, told the Journal. Members of his 16-person team, now fully remote, do better by developing ideas on their own and sharing them in writing. When they meet virtually, the meetings are tightly organized.

Yet some companies still believe that convening in person is more productive.

“In the more productive brainstorm sessions I’ve been a part of over the years, people get excited and blurt out new ideas or improvements to prior proposals, quickly advancing the seed of an idea, and leading to the broader group getting energized and feeling that it’s onto something,” Amazon CEO Andy Jassy wrote in a recent memo to explain why most employees must report to an office at least three days a week, starting this month, the Journal reported.

Lukas Kaiser, senior vice president of content at Westbrook Media in Los Angeles, told the Journal of his 70-30 theory: 70 percent of ideas in a brainstorming session are what he calls idiotic, but 30 percent of them have merit—a fair tradeoff, he thought.

Meg Amis, a marketing director in Philadelphia, told the Journal that the energy of everyone in a room yields an inclusive tone that can rally support for a project. “With anything that requires multiple people’s buy-in, it’s better to start with a brainstorming session because then everybody feels like they’re part of it,” she said.