We study the effect of setting a goal on performance using a randomized field experiment involving 1092 first-year university students. Students have private mentor-student meetings during the year. We instructed a random group of mentors to induce students to set a course-specific grade goal during a mentor-student meeting (goal treatment). A random subset of those mentors was further instructed to challenge students to increase this goal if deemed appropriate (raise treatment). We find that students in the goal treatment perform better as compared to students in the control group, and that students in the raise treatment do not perform significantly different from the control group. Finally, students who set a goal and are challenged to set a higher goal perform significantly worse than comparable students in the goal treatment.(joint with Michiel Souverijn)