A study at a company found that most meetings showed diminishing returns after 30 minutes, and little could be expected after 60 minutes  Moreover, the most productive meetings were those for which a clear time frame was established
For a meeting at the company to achieve maximum productivity, then, it needs to have a clear time frame and be no more than 30 minutes long
Most meetings at the company show diminishing returns after 30 minutes, according to a study.