Idiographic self-evaluation was conceptualized as the association between a rater's perceptions of trait descriptiveness and that rater's perceptions of trait desirability. In Study 1, self-evaluation was assessed using the 44 items of the Big Five Inventory (John & Donahue, 1994). A subset of 23 items, Like the full inventory, showed that most raters' self-evaluations were positive and stable. Study 2 showed that self-evaluation predicted self-esteem and (inversely) depression but not impression management or self-deception. Narcissism was negatively related to self-evaluation when self-esteem was controlled. An idiographic index of evaluative bias (self-enhancement or self-diminishment) was derived from the self-evaluation index by partialing out the group averages of descriptiveness and desirability ratings. In Study 3, this index of bias was compared with two difference-score indices: (1) the degree to which people rated themselves more or less favorably than they rated others and (2) the degree to which they rated themselves more or less favorably than they were rated by others. The idiographic index was independent of the two difference-score measures and showed greater self-enhancement. (C) 1998 Academic Press.