I'm amazed this is permitted at your university. If this is a regular practice, what have other people done?

Can it be arranged that you do "blind" grading? Grade papers that don't have names attached, but some identifying (for the prof) number?

@ElizabethHenning I have asked the professor, who told me that this is not the first time he has done this.

@Buffy I can certainly ask for this to be done.

I would also waiver on the side of caution. Imagine the outrage that you would receive if you ended up with the highest mark and it is revealed that you were responsible for grading everyone else’s work, regardless if the prof grades yours - it is terrible optics. I think there’s a clear ethical violation here that you should be very cautious about because this could blow up on you.

@D.Gray I will highlight that grades count for only 10% of the class, the rest of it going in a project and exams, however the issue you raise about the highest mark is a very pertinent one that I had not considered. I will be sure to consider it when I decide to whether to resign or not from this position.

The first paragraph is very hard to make sense of. Just to be perfectly clear: you'll be the official TA for this course you haven't taken yet, and you'll be paid for that work?

@Pierre Duluth I'm glad I could share some perspective with you. I would actually go and talk with your universities ethics board and get their opinion on the matter. What would be horrible for you is to be convinced that what you're doing is okay by your professor and department faculty (whether due to incompetence, miscommunications, etc, etc) and then have the powers that be come down upon you. Do your best to protect yourself from all angles.

@DanielR.Collins That is correct: I have some background in the course, but have not actually taken it. I will be paid for grading the assignments of the other students in the course.

@DanielR.Collins I have edited the question description to better explain the situation.

If you have enough knowledge to grade the course, why on earth are you taking the course?

@DJClayworth Sometimes it is not enough to have the knowledge, and having the documented training is needed (prerequisites, job requirements, etc).

Something like this used to be possible in the past, if the student was outstanding and it was clear that they would be far above the class in capabilities. Some famous students are known to have done that (I forgot the name, but remember reading about that). However, with university increasingly resembling school with proper grades, and established apparent fairness procedures, reproducible evaluations of student capabilities etc. (I am not saying this is really a good development), it is unwise to treat one member of the student cohort differently. Unless...

Maybe you can arrange to get credit for the course by taking an exam on the material right now? At which point you can be the TA without having to take the course at the same time.

Grading people you know happens quite often. In my mind this is not a big problem (even if it is somewhat uncomfortable). One should just make sure that the grading system is as transparent and objective as possible. The fact that you are also taking the course is what worries me a bit. Is it necessary for you to officially take it? Would it work for you to attend it without enrolling officially? I think this would make the situation healthier.

I'm absolutely astonished that this is a thing. What was the professor thinking?!

@CaptainEmacs: not only famous students. I used to run the Unix cluster of my uni dept, as a student. There was a course on Unix administration that I normally would have had to take but the teacher "waived it", as I was probably more knowledgeable than he was (it was not his area of expertise). I still had to have this course in my papers so I got it on the premise of what I was doing (for free) for the dept in that matter.

@LightnessRaceswithMonica The professor probably came from a period where universities were about education not about government-driven goals and assessments.

@CaptainEmacs While I agree with you about how the world of Universities has changed (and not necessarily for the better), I think this is a pretty clear conflict of interest irrespective of the setting/environment.

@LightnessRaceswithMonica Yeah, because everything is assessed. I came from a culture where assessments happen early in the studies (to weed out fellow-travelers) and at the end only (to provide a grade for the degree). Everything in between was based on participation.

@CaptainEmacs Well, you're certainly right that, if there were no grading, this situation would not have arisen.

You write "I will definitely be able to see if someone makes an obvious mistake in their proof that I, as a TA, would deduct points on." I strongly hope, that you would ALWAYS point out such a mistake to fellow students in your study group, whether you actually are the TA or not. After all, isn't that one of the reasons why people form study groups?