This year, I decided to apply to a top program in my field in a very good university.

Part of my application needed to include 3 to 4 letters of recommendation, one of them from my advisor / co-advisor.

My co-advisor told me she would be willing to write a letter of recommendation for me. I trusted her, and added her email to my application. However, she told me she wanted to read my research proposal. I sent it to her, and then, she told she could no longer support me with such a proposal. In addition, she told me she didn’t receive the link to recommend me. I made the corrections she told me to do, sent the new proposal to her, and didn’t hear back until I sent her an email saying that she could sent her letter to a general email address in case there is an issue with the link. Then, I received an email from the university system saying she had submitted her letter with the link she told me she didn’t receive. Then, she wrote to me to say that her letter will remain confidential because it « gives more weight to your application » but that she supported this new project.

However, I am not sure how to think of it. All my other professors asked for my resume to write my letter and told me things like « it was a pleasure to write for you », not her. I got a very high grade to my dissertation, but there were tensions between me and my advisor due to different character so I didn’t ask him for a letter.

As I trusted her initially, I also talked to her about my doubts for PhD applications, whether or not I wanted to stay in my country etc so I am afraid she would speak of that doubts in my letter.

I have really good grades all along my bachelor and my master (+3.9). But do you think my application could be sink by ONE bad letter of recommendation by my co-supervisor and three glowing letters from professors?

Thank you

  • 18
    I think you are jumping to conclusions - it seems this person was willing to take the time to give you real tips and help with your proposal (probably made it much better) and then was happy enough with what you did that she wrote you a letter. I don't know why you think it would be bad.
    – Dawn
    Commented Jan 7, 2023 at 5:01
  • 3
    I've flagged this one for "strongly depends on personal factors" because the bulk of the text and the title are of that quality. The final question posed in the body is maybe fine, but somewhat overwhelmed by the rest.
    – user137975
    Commented Jan 7, 2023 at 18:37
  • There was a gap between her saying she did not receive the link and her submitting it via the link. During that interval she might have received the link, found it was in her spam folder (some I have received ended there), asked them to resend it, or something else. Commented Jan 8, 2023 at 15:13

1 Answer 1


It is fruitless to speculate. There is no formula for evaluating letters, and you don't even know what your co-supervisor wrote. It could be that her letter was fine and this is much ado about nothing. In general, faculty will decline to write a letter rather than writing a very negative one; indeed, writing an extremely negative letter may make the recommender look worse than the student.

But to the larger question, whether one letter can sink an application, it comes down to the overall impression that is created. If the negative letter is vague, or a rant, and is generally incongruous with the rest of the application, then is unlikely to have much impact. On the other hand, if the negative letter is clear and specific, if it gives the impression of being fair and written by someone who knows you well, and if its strong negative comments do not contradict the positive comments from the other letter-writers, then the effect could certainly affect the outcome.

  • Thank you for your answer! Yes it’s true that it would not be good for her too… it’s just that I don’t understand why she wrote me it would remain confidential. I didn’t even think about asking the university to read my letter so why did she specifies it and none of my other professors? Thank you for your answer.
    – Cctte
    Commented Jan 7, 2023 at 8:37
  • 6
    @Cctte That is not uncommon that professors do not share what they write in the LORs to students. Sometimes, they are expected not to do it.
    – Neuchâtel
    Commented Jan 7, 2023 at 9:55
  • 7
    @Cctte take the advice from the first sentence: you have done what you could. Now it is time to forget that this exists until you hear back from that university. Thinking about it will only hurt you. Do something productive instead. Commented Jan 7, 2023 at 10:13

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