In a recent study, the leadership ability of narcissists was tested. It has often been thought that narcissists make good leaders due to their self-confidence. However, in the study, it was shown that groups led by narcissists often made poor choices (in the case of this study, the choice was in deciding who to hire). These groups also were shown to share less information with each other. However, the study also showed that the narcissistic leaders were rated more highly by their group members than the leaders who were not narcissists. Thus, the study shows that while narcissists appear to be good leaders to those around them, they actually are not.
Source: Freakonomics Blog