Understanding how leaders make decisions, and in particular, whether they are capable of displaying good judgment, is critical to understanding organizational effectiveness. To date, most efforts aimed at explaining or predicting judgment have focused on critical thinking, IQ, or other cognitive abilities. However, this paints an incomplete picture of an individual’s thinking and decision-making style. Indeed, cognitive ability may play a major role when it comes to learning new things and solving logical problems, but most of the problems leaders encounter in organizations are ill-defined, and their critical decisions are often made under conditions of uncertainty. In fact, many of the key decisions leaders make are better explained in terms of personality than intelligence.