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How to Ask for a Letter of Recommendation

The end of the year is approaching at an alarming rate, which means that many students will require letters of recommendations for graduate school or jobs. These letters are written by more senior academics and researchers at the busiest time of the year, when they’re handling other responsibilities like research, teaching, grant writing, and reviewing, and may be writing a dozen letters on top of it all. The purpose of this post is to guide applicants on how to ask for a letter of recommendation, simultaneously strengthening the applicant’s package, and making the letter writing process as painless as possible for their writers. Feel free to share this with anyone applying for grad school or jobs. If someone is asking you for a letter, you could share this post with them, so they know what you need.

Note that this document is written by a computer scientist and intended for applications to computer science things, and may or may not carry over to other fields.

Whom to ask

Ask people who know you and your work well. Ideally people who you’ve worked on research with. Their words will carry the most influence for whatever position you’re applying to. On the other hand, if you don’t have a letter from someone you did a major research project with (especially when applying for grad school), this is a red flag. Aim to have at least one such letter. While grad school applications typically solicit three letters of recommendation, very few people have all focused on research (I personally had two, from co-advisors on one project).

Some have suggested having someone “at arm’s length” is beneficial for faculty applications (and anything that comes later, including awards and fellowships), in order to show that your work is known more broadly in the community. 

Letters from people who did nothing more than teach you a course are typically valued much less than research-based letters. Nonetheless, most grad school applicants will have at least one or two such letters, since it is rare to have the opportunity to do research projects with three different advisors. If you must, try to request letters from people who you left an impression on, or otherwise had meaningful interactions with. Try to avoid letters from people who can do nothing more than repeat information on your CV/transcript: these letters are often very short and uninformative, and as with any such letter, are unlikely to help your case (and may even hurt it).

When to ask

Please ask well in advance. As a rough rule of thumb, by late October is reasonable for “standard” deadlines which are in December, which is common for CS grad school, postdoc, and faculty applications. You might have to ask earlier if there are earlier deadlines (which is the case for some postdoc applications), but give at least a 6 week lead time. Try to mention the earliest deadline in your email request.

Asking early also benefits the applicant. You should have a solid picture about these key details of your application well in advance.

I may still agree to write a letter for you even after the end of October, but chances decrease the longer you wait. On the other hand, I am more likely to agree to late requests if I know you very well or we have worked together very closely. However, I would still be annoyed, and you probably want to avoid annoying your allies in this process.

What to provide

You should give your letter writers as much information as possible. They might not use all of it, but it is good to have on hand when they are inevitably writing letters at 4 AM the day before after the deadline. I’m writing this as a catch-all list, so some points might not be relevant for the position you’re applying to. Say, when you’re applying for faculty positions, they don’t need to know your undergraduate grades. The goal is to give your writers the gist of who you’re trying to market yourself as, so they can support your story as best they can.

This doesn’t all need to be provided when you first ask, but please share it as early as possible. Make it as easy to find as you can. For example, a single email with everything as an attachment, and a clear title to the email such as “X’s application materials”. You could also share a link to a Dropbox or Google Drive folder with all the materials. This has the benefit that you can include preliminary versions of your materials, and update them as you refine them.


  • A shared spreadsheet with a list of all the places you’re applying to, the deadlines, any special instructions for letter submission, and a space to mark when the letter is submitted.
  • Your research statement/statement of purpose
  • Your CV

Optional but recommended:

  • Anything else that the application asks you for, e.g. your cover letter, teaching statement,  diversity statement, transcript.
  • Who else is writing letters for you, and what your relationship to them is.
  • A brief summary of the work you’ve done or the contributions you’ve made with the recommender, to refresh their memory.

The last one is helpful since I like to know what “role” I’m playing. Am I your lead letter writer who people will look to first? Or am I the third letter, mostly confirming what other people already know? There may also be some unique perspective I can give, based on who your other reviewers are.

Finally, be sure to waive your right to view the letter when requesting it. I personally will not write a letter if this right has not been waived (and I would also be annoyed to receive such a request). It’s also not to your advantage to have such a letter, since a reader wouldn’t be able to trust what the writer wrote.


To the best of my knowledge, it is not customary in Computer Science to send gifts to your letter writers. You should just thank them genuinely, and pass on the favour when you are in a similar position of power.

What if…

It has been brought to my attention that, unfortunately, many letter writers ask the applicant for either a draft or full letter, which they simply sign. I could write a whole post on this topic, but in short, I consider this unacceptable behaviour from the perspective of the letter writer, and I urge them to rethink this practice. 

But what should the applicant do when put in this position? It helps if you can see what typical academic recommendation letters look like, since they have a certain tone, but access to such letters is generally out of the reach of most applicants. My recommendation is to be positive (now is not the time for modesty), but don’t lie (these things can follow you around for longer than you might think). Try to make the first paragraph a brief summary that conveys the overall sentiment of the letter. In subsequent paragraphs, you should describe the research you worked on with the letter writer (don’t assume the reader is highly familiar with the topic, but be succinct in terms of background), as well as your specific contributions to the project. Include anecdotes, if appropriate. This may be awkward, but you have been put into an awkward position.

Statement of Purpose?

You probably haven’t written anything like a Statement of Purpose before. Here’s two resources (1, 2), by Boaz Barak and Yisong Yue, where they describe what goes into a Statement of Purpose. Naama Ben-David‘s statement is used as an example.


Thanks to Anand Sarwate, Thomas Steinke, and Jon Ullman for helpful comments.


2 thoughts on “How to Ask for a Letter of Recommendation”

    1. It’s a good question, which depends on how reliable the faculty is. For a reasonably reliable faculty, I’d say polite reminders a week before the first deadline (in case it slipped their mind), and the day before the deadline would be reasonable. I don’t know how I’d change this for less reliable faculty, except that I’d be more worried whether they’ll come through…

      The timeline in the email seems reasonable, but the earlier you ask, the more likely people are to say yes.


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