Formulas to predict presidential greatness on the Maranell index were constructed for 29 presidents from Washington to L. Johnson. When a zeitgeist variable, derived from the historian A. M. Schlesinger, Jr.'s (1986) work on the public purpose-private interest cycle of American political history, served as the initial predictor and stepwise selection was made from a personological pool and then from a situational pool, a 6-variable formula containing 5 personological variables accounted for 91% of the greatness variance. With free stepwise regression, years served and 6 personological predictors accounted for 94% of the greatness variance. Contrary to Simonton's (1987) attributional interpretation, a dispositional basis for presidential greatness may exist. The results also suggest that public purpose phases bring forth presidents who exhibit the personological characteristics most related to historians' acclaim for presidential leadership.
