If you think it’s tough for your dentist to squeeze you in, try getting on the calendars of 150 CEOs.

That is what College of Business Assistant Professor Amanda Moss-Cowan and colleagues had to do to discover what it takes to ascend to the corner office. She and colleagues from the the University of Oxford in the United Kingdom, with assistance from executive search firm Heidrick & Struggles, conducted 151 interviews on six continents; sitting down with 139 men and 12 women—numbers reflective of the current gender breakdown throughout corporate leadership.

Convincing busy CEOs to agree to an hour-long conversation was challenging, and that was particularly true for the women.  “Everyone wants to interview them,” said Moss-Cowan. “They can’t spend all their time talking about being a woman; they have a company to run.”

When the team published an article in the journal Human Resource Management in December 2017, the findings on women CEOs went viral.

The team discovered that with gender stereotypes persisting, women rely on themselves rather than a network of sponsors to succeed. Women accept, rather than celebrate, their drive and ambition, and struggle with personal tradeoffs. They also hesitate to stretch for a promotion until they are 110 percent confident. Men, on the other hand, feel capable even when they don’t have all the skills needed, Moss-Cowan explained.

And gender issues follow women to the top. “The males often said women CEOs should not be too masculine. They have to walk a tightrope: be assertive, but not too bossy,” she said.

Yet, she is encouraged to see more women succeeding. “I’m hopeful women coming up now will have an easier time and not be held to these perilous standards,” Moss-Cowan said.

The study transcended gender, with several interesting findings, and Moss-Cowan made an invaluable observation that applies no matter your place in the pecking order: During interviews, not once did any of the CEOs take a call or even glance at their phones. They focused on the business at hand.