Most top graduate programs require at least 3 recommendation letters. Do students who apply to such programs (and have a reasonable chance to get in) typically have such extensive research experience that they know three professors who can write in detail about their research? Or is it more common for such students to have some recommendation letters from faculty who can confirm that the applicant is competent (for example because they did very well in their class, won an award, ...) but with whom they have not worked much personally?

I understand it would be ideal to get all letters from faculty with whom you have worked closely on a research problem. But I wonder how commonly this actually happens, especially considering the fact that the final undergraduate year typically cannot be taken into account for applications in fall.

If it depends much on the discipline, I'm in physics.

  • It's totally fine to have mediocre letters (e.g. from relevant professors whose classes you enjoyed and did well in). Just make sure there's at least one stellar one in there about your research.
    – user541686
    Aug 22, 2014 at 5:44
  • I had two from professors I did research with and one from my internship boss. Dec 27, 2014 at 13:42

3 Answers 3


In general, I don't think all that many students have three unique reference letters, all of whom can vouch for research ability. Two is quite common, as most undergraduates who pursue graduate degrees (at least in the sciences) do have some research experience at their home universities. Many of them also pursue a summer research project separate from their main undergraduate research project (or projects), providing another reference.

But I do agree that the third letter usually comes from a non-research source. I wouldn't even necessarily expect a third research letter.


I have reviewed PhD applications in Communication, Computer Science, HCI, and Informatics. I'll answer questions first:

  • It is not typical, in my experience, for students who apply to programs to have three faculty write letters that speak directly about extensive first-hand experience working on research with the candidate.
  • It is most common, in my experience, to have one or two letters from faculty with extensive first hand experience overseeing research (often a coauthor on a paper) and one or two letters from people who know the candidate somewhat less well.

You don't need every letter to give a first hand description of your research experience. If you don't have anybody who talks about it, it will be a problem.

You want letters from people that:

  • Describe your ability to do excellent research in the area or field you are applying.
  • Explain how you are very smart, skilled, hardworking, generous, easy to work with, etc.
  • Demonstrates enough history and experience with you that we can trust the opinions expressed in the letters to be informed and accurate.
  • Are from colleagues whose opinions the letter recipient will know and respect.

Not every letter needs to do every one of these things. The important that the entire package convinces the reader that they're not taking a risk by accepting the student. Do what you can. If no one person can say everything, it's totally OK to the fact that you're turning in multiple letters to give a more full picture.

  • Nobody expects every letter to do all of these things. — Maybe not in your department/field.
    – JeffE
    Aug 22, 2014 at 2:36
  • This is a useful answer on its own, but does not really answer the question.
    – Onsager
    Aug 22, 2014 at 11:49
  • @JeffE Could you please add an answer corresponding to CS then?
    – whoisit
    Dec 6, 2022 at 11:43
  • I reworked that sentence. I suppose somebody might expect that, even if I think it's silly for them to want that. I changed it to say "Not every letter needs to do every one of these things."
    – mako
    Dec 7, 2022 at 20:53
  • @Onsager I've added text to more directly answer the question.
    – mako
    Dec 7, 2022 at 20:59

Which field are you in? In the humanities and social sciences, we expect letters from faculty you've taken seminars in, not just your thesis advisor.

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