What is the proper etiquette when declining a professor's Capstone project offer after I myself applied for it?

Question

In my department, every undergraduate (including me) has to do a Capstone project with a professor in order to graduate. Students need the professor's consent prior to declaring that the supervisor for the project is that professor. However, the rules do not indicate whether students can obtain multiple professors' consents and choose one of them as the supervisor (thus declining all others). I asked fellow students and they all talked with only one professor.

I talked to two professors and they both are happy to be my supervisor and now I have to choose only one of them. Declining a professor's "offer" [1] might be an issue to the professor because I suppose they have to make changes on their schedule (though the consent must be obtained two months before the project).

Both professors are fairly respectable and I do not want to be distrusted by them. What is the proper etiquette when declining one of them?

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[1]: They did not actually give a formal consent. They jumped directly into the discussion of interests and schedules, as if they have already treated me as their supervisee.

Answer 1

I hate to say it, but professors aren't chomping at the bit to add one-on-one undergraduate supervision to their schedule. It sounds like something that regularly happens in your department - and I'm sure professors often enjoy it and do a good job - but a professor is not going to be distraught if you don't end up working with them.

A simple email suffices (see also this question):

Thank you for the discussion yesterday, Professor X. I also spoke with Professor Y and her interests align with my goals for this project more, so I will be doing my capstone with her.

Thanks again, and see you around,

durianice

As Rmano recommended in the comments, inform them as soon as possible so they can manage their own requirements.

Answer 2

Okay, so this is my experience of choosing a professor for my graduate research project.

When you approach a professor and talk to them, they do not consider that you have chosen them as your supervisor. Therefore, you do not need to feel guilty about declining their offers because:

Only in the second meeting or so, you can choose or agree with them on the selected direction of the project. Then, the professors will create a paper or a list confirming that you are their student and send to the department.

Even if you discussed your chosen direction in the first meeting with them, some professors might think that you have already made your choice and later change your mind. However, this is fine because the significance of the project allows you to do so.

And this is what I think on the etiquette:

Whether it is considered proper etiquette or not doesn't depend on the fact that you approached a professor and then declined their offer, but rather on how you did it. In my opinion, etiquette is about looking into a professor's bio, their specialty, and the usual direction of their previous students before approaching them. This way, when you decline their offer, the reason will be specific and professional.