"Overconfidence
People tend to overestimate their own abilities, knowledge and skills. For example, if you ask 100 people if they are better than average drivers, then you might not be surprised if more than 50% of them reply “yes”!
Moreover, studies show that the discrepancy between accuracy and overconfidence increases (in all but the simplest tasks) as the respondent is more knowledgeable! (Accuracy increases to a modest degree but confidence increases to a much larger degree. ) If this is true then it may not be wise to pass the Subject ST5 exam!
Overconfidence could therefore be a potentially serious problem in fields such as investment where most of the participants are likely to be highly knowledgeable.
Moreover, the available evidence suggests that even when people are aware that they are overconfident they remain so."