Leadership may be defined as both a process and a property. Research shows that some attributes common to successful leaders (characteristics, knowledge, and skills) can be significantly influenced by planned education or training. In the process of developing a leadership assessment instrument, a study specified four broad tasks that leaders are expected to perform and identified 37 attributes hypothesized to be most likely to predispose desirable leadership behaviors. The 37 attributes were assembled into the Leader Attributes Inventory (LAI). Three forms are available: (1) an other-rating form to assess an individual's perception of the extent to which she or he believes some other individual possesses each leader attribute; (2) a self-rating form to assess an individual's perception of the extent to which she or he currently possesses each attribute; and (3) a retrospective self-rating form. Studies have been conducted that provide evidence about LAI's usefulness in assessing leadership development. The consistency of LAI scores has been satisfactory. The LAI is suggested for evaluation of leadership development programs and for individual diagnosis. (29 references) (YLB)