New research suggests that leaders are perceived as most effective when they know when to be assertive and when to be non-assertive.
Original Research Article: Ames, D. R., & Flynn, F. J. (2007). What Breaks a Leader: the Curvilinear Relation Between Assertiveness and Leadership. Journal of Personality and Social Psychology, 92(2), 307-324.
Read a synopsis or get a copy at: www.apa.org/releases/good_leaders.html