Most studies of the determinants of understanding in economics focus on performance in a single course or standardized exam. Taking advantage of a large data set available at the U.S. Naval Academy (USNA), the authors examined the performance of economics majors over an entire curriculum. They found that gender was not a significant predictor of grade point average in economics courses, but grades of male minority students were lower than their counterparts'. The USNA dataset also provides information on Scholastic Aptitude Test scores and personality variables, allowing exploration of their influence on performance. Students characterized as "judging types" (described as decisive, organized, and self-regimented) generally performed better than did students characterized as "perceiving types" (described as curious, adaptable, and spontaneous). (Contains 3 tables and 7 notes.)