It's no secret that everyone hates meetings. There's nothing worse than getting 15 people together to make decisions, then getting sidetracked, running out of time, and being forced to schedule a follow-up meeting.

Michael C. Mankins, a San Francisco-based partner at management consulting firm Bain & Company, says too many poorly-run meetings hamstring productivity. He writes in Harvard Business Review about how Metcalfe's law of telecommunications networks applies to executives connected via email. "The law has a dark side: As the cost of one-to-one and one-to-many interactions declines, the number of these interactions increases dramatically. And people are interacting more than ever," he writes. "Worst of all, they are calling meetings."

The ease of calling a meeting, which used to require assistants exchanging schedule information over the phone to find an open time slot, has made time-sucking and money-wasting meetings far more frequent. "Now all they need to do is check Outlook or a similar program and send a quick email. As a result, most executives are spending 20 hours or more every week in meetings. And one meeting usually spawns many more," Mankins writes. At Bain, Mankins and his colleagues calculated that a single weekly executive committee meeting at a large company can generate about 300,000 hours of preparation time each year.

If this sounds like your executive team--needlessly squandering time and money sitting in a room, Mankins has a few suggestions. The first is to think of your meetings the way you think of your money. "You can manage [meetings] as closely as you manage every investment," he writes.

Don't call a meeting by default

Meetings should be reserved only to accomplish specific tasks. "Don't hold a meeting for the sake of holding a meeting. Meetings are great for some tasks, like gathering input and coming to a group decision. They aren't so good for other tasks, such as drafting a strategy document," Mankins writes. "Before calling a meeting, decide whether it's really the best way to get the job done."

Manage the invite list

Think of the door to your meetings like a door to a nightclub with a bouncer turning people away. Meetings should have a tight invite-only list. "In many companies it's bad form not to invite lots of people to a meeting. What people don't realize is that every additional attendee adds cost. Unnecessary attendees also get in the way," Mankins writes. "Remember the Rule of 7, which states that every attendee over seven reduces the likelihood of making a good, quick, executable decision by 10 percent. Once you hit 16 or 17, your decision effectiveness is close to zero."

Only hold 30-minute meetings

An hour is too long for a group of executives, let alone the entire company, to be sitting in one room talking. Mankins advises keeping meetings short. "Not too long ago, most companies called 30-minute meetings. Now the typical default time has grown to 60 minutes, even though every additional minute generates more cost," he writes. "As my colleagues and I recently noted in HBR, one company established a rule: If a meeting was to last more than 90 minutes, it required approval by an executive two layers up from the convener. This rule quickly cut meeting time."

Manage every minute

If you're calling a meeting, that means there must be important decisions or a serious announcement made. Be frugal with the time and manage each minute like money. Mankins suggests following simple disciplines: "Clarify the purpose of every meeting. Spell out people's roles in decisions. Create a decision log that captures every decision made in a meeting," he writes. If the log turns out to be blank, you should question why the meeting was called in the first place.