Duties vary by GA assignment and what the responsibilities and interests of the GAs' supervising professors are. Most GAs (including myself) are shared by 2 professors. All GAs are responsible for occasionally grading assignments, covering classes, proctoring exams, and research. Our department runs the Ohio Historical Center of Industry and Labor and some GAs are assigned to work at the museum. I'm assigned to the 2 professors in my dept that are editors in chief of academic journal, so while I do grade, cover classes, proctor, and research occasionally, most of my time is devoted to acting as the editorial assistant for one journal and as the assistant editor or the other.