Facebook is among the biggest and most successful tech companies in the world, and when its CEO offers job advice, it is a privilege for listeners. Mark Zuckerberg spoke at the Mobile World Congress (MWC) in Barcelona this week, and there he revealed what matters most to him when hiring an employee.

Facebook CEO Shares One Hiring Rule He Always Follows

Facebook CEO looks for the right match

His requirements seem pretty simple, as he told the audience, “I will only hire someone to work directly for me if I would work for that person. It’s a pretty good test and I think this rule has served me well.”

The Facebook CEO said only people whose values align with the company will get the opportunity to work with him and his team. “Facebook is not a company for everyone in the world,” he told.

Sheryl Sandberg is one such example, as she was hand-picked by Zuckerberg for her role as Facebook’s chief operating officer. Zuckerberg said she successfully passed the test. Sharing his experience of working with Sandberg, the CEO said he looks at her as a mentor and believes she has played an important role in making Facebook a business and “healthy organization.”

Staff count does not matter

The volume of staff at Facebook is not on par with that of other tech giants in Silicon Valley. For example, Google employs about 55,000 employees. Despite this, Facebook’s CEO attributes the social media giant’s success to its small staff size. More than a billion people around the world are served by Facebook, which has only about 10,000 staff, and this has been possible by modern technology.

Zuckerberg, whose net worth is around $35 billion, added that having faith in oneself also played an important role. He said no individual should get discouraged by the negative comments of people who believe lack of experience to be a major barrier. Giving himself as an example, the Facebook CEO said he started as early as 19, adding, “Don’t discount yourself, no matter what you’re doing.”