If you walk into Warren Buffett’s office, you might think you’d see his framed diploma from Columbia Business School. But you won’t. Instead, you’ll see proudly displayed on his wall a 1952 certificate for completing a $100 course on public speaking. It was while he was a 22-year-old at Columbia that he saw an ad in the paper for a Dale Carnegie public speaking course. “I went to Midtown, signed up, and gave them a check. But after I left, I swiftly stopped payment. I just couldn’t do it. I was that terrified,” he recounts now.

Warren Buffett says that learning how to be a good public speaker changed his life.

Fortunately, he went back, overcame his fear, and today he credits that $100 course with having changed his life. “In graduate school, you learn all this complicated stuff, but what’s really essential is being able to get others to follow your ideas,” he says.

And so it is for entrepreneurs. Every great entrepreneur has the ability to tell a crisp, clear, and compelling story about what she’s working on, and why it matters.

“In the modern world of business, it is useless to be a creative, original thinker unless you can also sell what you create.” —David Ogilvy, founder of Ogilvy & Mather and “Father of Advertising”

In the world of startups, one often hears of “pitch decks” — a set of slides used for a pitch. And while most people think of this in the context of fundraising, the fact is that successful entrepreneurs are pitching all the time for all sorts of reasons. Entrepreneurs are pitching customers, recruiting employees, convincing partners, telling the landlord why he should give them a discount on the rent. Pitching skills matter.

At Stanford, I make my students give a 3-minute pitch on their startup idea. I do the same with social entrepreneurs at Miller Center. They usually grumble about being given so little time, and tell me that their idea is so amazing they need more time to properly explain it! I respond by telling them that if they can’t sell it in 3 minutes they won’t be able to sell it in 30.

Telling a short story is hard. But it is so important. It’s important because it’s a powerful tool for an entrepreneur to have, but it’s also important because figuring out how to say it short helps you to develop clarity yourself on what it is you’re working on.

“If you can’t explain it simply, you don’t yet fully understand it.” —Albert Einstein

I once met an entrepreneur at a social event and asked him what he was working on. “Well,” he said, “there are a lot of grocery stores in the country,” and then he took a long sip from his glass of wine. “Their biggest facilities expense is cold storage,” he continued before having another sip of Zinfandel. Now I was intrigued. “We make a device that cuts that cost in half.”

Boom! I wanted to invest! In three short sentences, he told me the size of the market, the problem to be solved, and that he had a solution!

An inexperienced entrepreneur might have described the exact same startup this way: “We’ve developed a cloud-powered IoT device that uses proprietary algorithms to analyze operational data for mercantile customers, generating paradigm-changing results…..” I would have walked away from that guy.

Learn to tell the story crisply and clearly. Watch videos of Warren Buffett, or of Steve Jobs, or of Elon Musk. Take a public speaking course. As an entrepreneur, the ability to tell a crisp, clear, and compelling story is a skill that will serve you well.

Originally published on Medium.