Why do students major in Economics? Why is the proportion of women who study Economics so low? This study will assess whether students respond to messages about majoring in Economics, and whether this response varies by student gender. The experiment will occur in two phases. In the first phase, we will randomly assign students currently enrolled in Economics Principles courses to receive messages emphasizing the rewarding careers available to Economics majors or the financial returns to the major. These groups will be compared to students receiving no such messages and to a group receiving a "placebo" message with basic information about the major. In the second phase, all students receiving a grade of B- or better will receive a message after the course is over encouraging them to major in Economics. A randomly chosen subset of these students will receive a message encouraging them to persist in Economics even if their grade was disappointing. Results will shed light on student motivations to major in Economics, which messages can change their choices, and whether female students respond disproportionately to certain messages about the major.