Everyone knows meetings are a waste of time. In fact, management experts say they are a waste at least half the time that executives spend in them -- talking, debating and setting up the next meeting.

"How often we meet and the cost of unproductivity is the Achilles' heel of our vaunted American businesses," said Roger Mosvick, a St. Paul management consultant who has been watching executive behavior at meetings for 30 years. "We should cut our meeting time in half and improve decision making."

Mosvick is not alone in his views. Hardly anyone has a good word to say about meetings, though most every business considers them a key element of success. Surveys of executives and workers come to the same conclusion: Meetings are one of the most time-consuming and least productive activities in the workplace.

They are expensive, too, costing business up to $37 billion annually, primarily in wasted wages, said one expert on meetings.

Here's why. The typical meeting occurs with only two hours' notice and has no written agenda, or, if it has an agenda, the meeting often fails to cover it, according to a study done by the Annenberg School of Communications at the University of Southern California.

Furthermore, participants often believe their role in these meetings is limited. Of 903 managers at 36 companies who were asked about their last meeting, one-third said they had no impact on ultimate decision making. One-third felt pressure to back opinions they privately disagreed with.

Yet meetings matter in how decisions are made at most companies, and it is expected that there will be more meetings than ever in the 1990s as the economy increasingly centers on services and white-collar businesses.

"It is impossible to be regarded as a highly effective manager unless you run an effective meeting," said Walter A. Green, founder of Harrison Conference Services Inc., which hosts conferences at nine centers across the country.

According to research done by his company and Hofstra University, Green found that four out of five managers evaluate each other based on how they participate in a meeting, and 87 percent judge leadership based on how a person runs a meeting.

To cut down on badly run meetings that make everyone feel inefficient and indecisive, some companies have turned to rather unorthodox solutions, said Gini Johnson, head of the 3M Meeting Management Institute in Austin.

For example, chemical and synthetics manufacturer Hercules Inc. in Wilmington, Del., encourages clock watching. It has mounted big clocks at the back of every corporate conference room to keep a check on endless deliberations.

But the key to boosting effectiveness, consultants say, lies in understanding why meetings fail. That done, take remedial steps. Finally, learn how to address personality problems that can disrupt meetings.

Another key, consultants say, is to meet less. Executives spend up to 17 hours each week, or almost 40 percent of their working hours, in meetings, said meeting maven Mosvick.

Why are all those hours frittered away? "It's getting off track, being unprepared, having no agenda and interruptions," Mosvick said.

Mosvick emphasizes "the basics" when dealing with meeting problems. Some suggestions for making meeting time productive:

Sharply define who comes to meetings and give them an agenda two days in advance. Remember that many people don't know why they have been called to meet and are unprepared.

If you direct a meeting, set the stage with a three- to five-minute orientation speech. It helps focus attention, frames discussion and prevents drift, Mosvick said.

Incorporate dissent into the meeting structure. The worst business decisions would never be made if someone had had the courage to disagree, he said.

Let someone other than the boss run the meeting so the boss can stay cool and evaluate things as they happen. This also promotes discussion.

Record what takes place in a meeting and act on decisions reached. Appoint a meeting secretary, publish the minutes and write down who has promised to do what afterward; then follow up.

Learn how to turn the tables on troublemakers, Johnson suggested. Ask questions of the shy, cut off the domineering and force critics to offer solutions.

"You're not going to clean up all of the 50 percent that's wasted, and you probably shouldn't," Mosvick said. "But the fact that meetings may be bureaucratic and undemocratic does not mean that there cannot be room for creative ideas or good thinking."