March 5, 2015 3 min read

When it comes to onboarding new employees with whom he’ll work directly, Facebook CEO bears in mind a single guiding principle that he says has never steered him wrong.

“I will only hire someone to work directly for me if I would work for that person,” Zuckerberg told an audience gathered in Barcelona yesterday for the fourth installment of ‘Q&A with Mark,’ an ongoing series of town hall-style discussions.

While employers generally have more work to do than staffers to get it done, Zuckerberg says business owners should resist the urge to settle for lesser candidates in the name of manpower. “Over the long term,” he said, “you’re only going to be better if you get someone really good.”

Sheryl Sandberg is the perfect example of the kind of employee that, in an alternate universe, Zuckerberg says he would be happy to serve. Rather than outside of the company, he said, the most influential figures in his life are the colleagues he sees on a day-to-day basis. “Sheryl would be at the top of that list,” he noted, adding that she is largely responsible for the fact that 2 million businesses advertise on Facebook today.

Related: Mark Zuckerberg Calls the 'A-Ha!' Moment a Myth

If selecting candidates is one thing, attracting them is another. The key to wooing top talent, Zuckerberg said, is “just being upfront about what you stand for.” Facebook, for instance, is bullish on its mission to connect the world -- which he acknowledges isn’t a value or priority shared by everyone.

And finally, Zuckerberg had some wisdom to share in the realm of . His management style, he says, is fairly flexible. “[Employees] need the ability to fully exercise all their creativity and all their capacity, or else they’re not going to be having the biggest impact that they can have on the world, and they’re going to want to go do something else.”

At the same time, Zuckerberg has always striven to keep a streamlined team and to do as much work as possible himself. Facebook serves over a billion people, for instance, but counts a team of fewer than 10,000. “My first move when I was building Facebook wasn’t to hire a team of engineers to go build a product,” he explained. “I generally each step along the way have tried to do as much as I can myself."

Related: 'I Am Not a Cool Person': Our 5 Favorite Takeaways From Mark Zuckerberg's First Public Q&A