According to a New York Times article "Distilling the Wisdom of C.E.O.'s"
http://www.nytimes.com/2011/04/17/business/17excerpt.html based on a book "The Corner Office" by Adam Bryant, corporate success depends on
(1) passionate curiosity
(2) battle-hardened confidence
(3) team smarts
(4) a simple mind-set
(5) fearlessness
Maybe this is true, but in addition to retrospective studies, I would like to see prospective ones where people are rated on such qualities early in their careers and their success is tracked at regular intervals. I believe Terman did this.
Fearlessness can lead to great success or disaster. Even if the most successful people are fearless, it may not mean that everyone should be.