I am currently a teaching assistant for a lab course. I've been told to grade part of 1 of the 3 exams for the associated theory course. (There are multiple lab TAs and each is assigned one of the three exams.) The problem with this is that the theory course has its own TA, and best I can tell my responsibilities only cover the lab course.
In the past I was a TA for the theory course as well, and I had to grade almost everything (weekly homework, weekly quizzes, and 6 exams) for about 200 students in two separate lectures with two different professors. One professor offered to grade 2 of the 3 exams in his class to lighten my load, but I didn't request this. I am told my experience TAing the theory course was very typical (no help from the lab TAs). It was a lot of work, but it was manageable, and to be honest I'd rather be a TA for the theory course than the lab.
From what I hear, the theory course this time around has more than just a TA. The homeworks (easily over 1/2 the grading effort!) are graded by undergraduate graders to reduce the workload for the TA. Given the reduced amount of work for the theory TA and that I don't see these exams as part of my responsibilities, I am considering refusing this request as simply ridiculous.
After speaking with my advisor, he agreed that this is highly sketchy. He talked with some of the people involved and indicated this would not happen in the future, but for now I need to do what I was told. I get the impression that some department politics are involved and he doesn't want to step on more people's toes than necessary. But those people are stepping on my toes, and I honestly don't have the time to grade these exams.
I am meeting with the professor for the theory class soon to get the exams to grade. How should I bring up that I don't think grading these exams are my responsibility, and that I don't want to grade them? Any other ideas about how to handle this situation would be appreciated.
(I asked my advisor if he could figure out if there are any extenuating circumstances involved with this, e.g., the theory TA being ill. I could be accommodating in that case. While I did not get a direct answer to that, what my advisor told me when we last spoke about this indicates the answer is no. I do not know anything about the theory TA otherwise.)