What sets great leaders apart from their peers?

Good decision-making skills, an understanding of one’s entire company, and a knowledge of the broader industry are all decent qualities for business leaders to have. But there’s another characteristic that can help make the difference between being a good CEO and being a great one.

It’s a knack for building solid relationships.

Consulting company Navalent performed a 10-year longitudinal study on US business executives, conducting more than 2,700 leadership interviews and putting the data together in a statistical analysis to figure out what it is exactly that sets the most successful leaders apart from their peers. Of the four traits that researchers identified—presented in a Harvard Business Review note this week—the ability to form “deep, trusting relationships” was the most make-it-or-break-it attribute.

“Of the four dimensions, relational failure led to the quickest demise among second-best executives,” writes Ron Carucci, the co-founder of Navalent, in the article. Here’s more on that:

While exceptional executives led with a humble confidence that graciously extended care to others, second-best executives were inclined to manage perceptions, creating the illusion of collaboration while masking self-interested motives.

[The best] executives develop connection by investing heavily in their own emotional and social intelligence, actively solicit feedback about how others experience them, and learn to be vulnerable with their shortcomings to create trust with others.

While it may be obvious that good CEOs should possess the other three attributes identified by the study (keen business sense, industry knowledge, and good decision-making instincts), having trusting relationships with employers and stakeholders is an oft-overlooked and often challenging quality to develop. Recent research showed that only half of US employees trust their bosses. Studies also say bad relationships are a huge contributor to executive failure.

In the end, iconic leaders like Steve Jobs might give us the idea that displaying coldness and mystique make for the wildest success. But the study suggests they are the exception to the rule. Approachability and openness, it says, are actually much better traits to have. Aspiring CEOs with Machiavellian-style principles could consider changing up their tactics.