We spend a lot of time in meetings, but we’re bad at making them effective. In a 2005 survey of Microsoft Office users, Microsoft, found that workers spend 5.6 hours each week in meetings — nearly a full work day. Another study from the London School of Economics found that CEOs are spending around 18 hours a week on meetings.

Meetings are such a fixture in our work lives that we constantly hear the same advice: have an agenda, keep it short, don’t invite too many people. However, despite the commonality of this well-meaning advice, research from Harvard suggests that half of all meetings are unproductive.

Instead of following the same old advice and getting the same results, let’s look to some of the tech industry’s most powerful leaders, whose business lives are well-documented. By looking through past interviews, we discover unique, actionable advice and learn how top Silicon Valley CEOs keep their meetings effective.

Marissa Mayer: CEO, Yahoo

1. Streamline decision making with data.

Mayer believes that numbers and facts are essential to having effective meetings. She thinks of data as the great equalizer: whether you’re an intern or a VP, you can have your way as long as you have the data to prove your claims. By making decisions with metrics, she can avoid lengthy debates stemming from opinions and organizational politics. Businessweek offered a peek into Mayer’s process:

A caveat: while dependence on data can speed up decision-making, it can also turn off teammates who work with qualitative information. Mayer alienated her designers when she tested 41 variations of blue in order to get the optimal color for an element on a webpage.

2. Ask questions to resolve problems once and for all.

Mayer relentlessly asks follow-up questions to ensure that her team isn’t working from poorly sourced data or assumptions. Faulty assumptions can lead to backtracking on previous decisions down the road, which means wasted time, resources and more meetings. In Mayer’s world, assumptions have no place in meetings, and if you’re not ready to back up your claims, you’re not ready to present your ideas.

Mayer’s expects her team to be able to confidently answer her questions. FromBusiness Insider:

3. Use the micro-meeting.

While at Google, Mayer averaged 70 meetings per week. How did she manage all these meetings while still getting her own work done?

Mayer uses the micro-meeting: she allows people to book meetings as short as 10 minutes. Just because your calendar program defaults a meeting to 30 minutes, that doesn’t mean you need 30 minutes. An uninterrupted 30-minute block in her calendar is rare, so if you really need to speak to Mayer about something, make it quick.

There’s an adage in project management: work expands to the time you schedule for it. By pushing people to say what they need to say in 10 minutes, Mayer was able to meet more people in less time.

Elon Musk: CEO, Tesla / CEO & CTO, SpaceX

1. Argue with facts, not experiences.

To Musk, decisions should not be based on prior experiences. He encourages thinking based on “first principles” — boiling a situation down to its basic, fundamental truths and then reasoning up from there.

An example of first principles thinking: when Musk was estimating the cost of building the first SpaceX rockets, he could have simply used comparable products on the market as a benchmark. Making decisions using “common knowledge” is the antithesis of first principles thinking. Instead, his team analyzed the necessary parts of a rocket, then researched the prices of the raw materials of parts firsthand. As a result, the SpaceX team was surprised to learn that they could build a rocket that cost “around two percent of the typical price.”

In meetings, arguing with facts and first principles takes a lot more mental energy, but doing so can improve the quality of your decisions. By looking at a situation from the bottom up, Musk prevents intellectually lazy arguments like “well, that’s how much a rocket costs” or “that’s how we did it at NASA.”

2. Challenge your team to be ultra-prepared.

As CEO of two industry-changing companies like Tesla and SpaceX, Elon Musk works nearly seven days a week, with his hands in nearly every part of each business. As a result, he is a subject matter expert in nearly all aspects of his companies. This pushes his employees to be thoroughly prepared for meetings. An anonymous Musk employee weighed in on Quora:

Musk leads by example by consistently bringing his A-game to meetings, setting the standard for everyone to follow. As a boss, you don’t need to work seven days a week, but know that your perceived work ethic sets the tone for the whole company to follow. Stay sharp at your meetings and your employees will take your cue.

3. Remind them of the long-term vision.

After SpaceX experienced the third failed launch of Falcon 1, the pressure was mounting on the company. Musk knew that they had to quickly get back on their feet and deliver a successful fourth launch as soon as possible.

Musk addressed his overworked, demoralized and disappointed team in a meeting, then immediately got them to work even harder to deliver a nearly flawless launch less than two months later. How did he do it? In that pivotal meeting, he simply reiterated SpaceX’s goal: to launch a rocket into orbit. He emphatically promised them victory, saying “for my part, I will never give up, and I mean never.” Within hours, the team started working on the solution.

This was a critical moment in perhaps the most important meeting in the young company’s history. Musk knew that he had to remind everyone of what they were working toward, energizing his team and giving them the focus to complete the difficult tasks that lay ahead.

When working on large projects, teams can sometimes get caught in the weeds and forget how their work ties into the bigger picture. Smart leaders like Musk know when they need to step into a meeting to give their teams a much-needed shot in the arm.

Steve Jobs: Former CEO, Apple

1. Make your meetings informal, constant events.

Like Musk, who has his fingers in every part of his companies, Entrepreneur Magazine tells us that Steve Jobs liked to be constantly kept in the loop:

“At Apple, because quality is stressed over quantity, meetings are informal and visible progress is made on a weekly — if not daily — basis. Keeping your team in sync is not something you do once a week. It’s something you do every day.”

We know that Jobs aimed to run Apple “like a startup” — these meetings were not to micromanage his leadership team, it was because he wanted to have insights into all aspects of the business.

Go ahead and take a page out of his playbook: have a weekly meeting where you walk through the whole business. Don’t make any big changes to the agenda. In an interview with CNN, Jobs explained his reasoning:

2. Keep meetings as small as possible.

Jobs had a disdain for meetings that had too many people. He wanted people to be working, not passively sitting in a boardroom. If people didn’t have a lot to contribute, they’re better off spending time somewhere else.

During a weekly meeting with Apple’s ad agency, Jobs surveyed the room and found someone that did not normally attend. After asking who she was, he curtly replied, “I don’t think we need you in this meeting” then went back to his agenda without skipping a beat. But he also applied this standard to himself when faced with overpopulated meetings. Invited by President Obama to a meeting with other tech luminaries, Jobs famously declined because he felt that the invitation list had grown too long.

He had zero tolerance for spectators, even if that spectator was himself. Everyone in the meeting has to be an essential participant who can add value.

Invited by President Obama to a meeting with other tech luminaries, Jobs famously declined.

3. Hold people publicly accountable.

Like other companies, meetings at Apple end with next steps. When Apple employees divide up action items in a meeting, each task is assigned to a D.R.I. — a directly responsible individual. By making someone publicly accountable for the task, it can increase the pressure to ensure the task is completed by the next meeting.

Since meetings happen frequently, and the teams are smaller, the spotlight shines brighter on the people who own tasks. This public accountability is one of the ways Apple teams push people to perform at a higher level.

Lack of clear ownership can wreak havoc on projects, especially when it comes to large, multi-disciplinary teams. Having a D.R.I. for every task, however minor, ensures that all meeting action items get completed.