Using our data, Professor Deniz Ones of the University of Minnesota identified the following personality factors as predictors of presidential success:

Rated Intelligence - Intelligence is related to success in almost any complicated job, from CEO to NFL quarterback. Although we did not have intelligence test scores, we did ask our raters how intelligent, inventive, insightful, complex, and wise they perceived the various presidents to be. Those that received high ratings, like Jefferson, Teddy Roosevelt, and Wilson, performed better than those who are rated as less gifted, like Harding.

Assertiveness, or dominance, is the capacity to influence through one's presence and ideas. It is the single most important trait to presidential success. Presidents are an assertive group, and on the average score higher than eight of ten typical Americans. Better presidents like the Roosevelts, Wilson, and Jackson score higher than average chief executives. Truman was the only successful president who was less assertive than his peers. Low scorers include Harding, Taft, and Coolidge.

Positive Emotions - A president's optimism and enthusiasm are important for performance on the job, but also for getting elected. Enthusiastic and high spirited presidents like the Roosevelts, Clinton, and Kennedy are typically more successful; low scorers are reserved and serious, like J. Q. Adams, Hoover, and Nixon. Washington was the only truly successful low scorer on this scale.

Activity Level - Highly energetic chief executives like TR, LBJ, and Carter tend to be rated higher on this scale by historians than more placid characters like Grant, Taft, and Coolidge.

Achievement striving (having high goals and working towards them in a systematic and focused manner) is an obvious asset and is related to success in most all walks of life apart from the arts. Two of the lowest scorers, Grant and Harding, are widely regarded as presidential failures. High scorers include a number of undisputed "greats" like Teddy Roosevelt, Wilson, and Washington, but also more ambiguous performers such as Carter, Nixon, and LBJ.

Low Straightforwardness - Historians tell us that a president's credibility is essential to the ability to lead. Yet, the tendency and ability to deceive is correlated with historians' ratings of presidential success. Great presidents, such as Lincoln and FDR, have tended to bend the truth more than a little. Both managed to be both a moral leader and an artful politician. Grant and Fillmore were more honest, but also less effective.

Tender-Mindedness (concern for the less fortunate) predicts both presidential success and ethical behavior on the job. FDR and Lincoln scored high on this quality, while Buchanan and Nixon scored low.

Competence - High scorers on this scale seek appropriate information when faced with a decision, have good judgment, and are broadly capable - like Washington and Eisenhower. Low scores include the lowest ranked presidents Harding and Grant, but also the impetuous and successful Andrew Jackson.

Low Vulnerability - Presidents who feel unnerved by stress and unable to cope with problems on their own (score high on Vulnerability) are likely to be given low marks by historians. Emotionally hardy presidents, like Washington and Teddy Roosevelt, tend to do better than more Vulnerable chief executives, like Harding and the Adams's.

These are the only traits that have been empirically shown to have a distinct and unique relation to presidential success. "Character" was unrelated to historians' rating of presidential greatness.