Competence is inversely proportional to confidence

1. The Dunning–Kruger effect is a psychological phenomenon in which lower skilled people tend to suffer from the illusion of superiority, consistently rating their abilities as "above average." This effect has popularized the phrase: "competence is inversely proportional to confidence." In one example, 87% of Stanford MBA students rated themselves in the top 50% of their peers.
In my opinion, it would be interesting to observe the career outcomes of this population both based on their actual rank among peers (competence) and their perceived rank among their peers (confidence) and see the interplay of these variables in determining success. In other words, are less confident people with more competence relatively more successful or is high confidence level enough to a certain extend in compensating for their relative "incompetence" and providing a psychological frame-work for overall success? After-all, the surveyed population is Stanford MBA students, they do all have some baseline competence that is probably above general average.
Of an interesting note, when individuals are given exceedingly difficult tasks, they tend to underestimate their competence.