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Letters of recommendation

Letters of recommendation are required for most positions above internships, and sometimes even for internships. They are by far the most important component of your application, but you do not have full control over them since they are written by others.

Typically, you will be asked for the names and emails of your references, and these references will be directly asked for a letter, ensuring that they can speak freely since you cannot see the contents of the letter.

Unfortunately, academic expectations for letters of recommendation in top universities often do not match what many people think of as a letter of recommendation. For instance, a letter writer may genuinely believe they are writing a very strong letter, yet their letter could be perceived as weak by academic readers. You should suggest that your letter writers read the “Writing a letter” part of this page below, to help them help you. Regardless of what your references think is a good way to write a letter, the guide below is what schools such as EPFL actually want, and not following it will penalize your application.

Asking for letters

You will typically need 3 references for a PhD position, from people who can talk about factors important for the job such as your research abilities and your attitude. See the “Writing a letter” part below for examples of what letter writers are expected to talk about. In practice, most people have not done research with 3 advisors before starting a PhD. It’s acceptable to have one or even two letters from people who merely taught a course you got a good grade in, or people who worked with you at an industry job. If you mention anyone specific as a past collaborator in your statement of purpose or resume, you should get a letter from them, or explain why you cannot.

You should email people who you would like a reference from by asking them whether they can write “a strong letter of recommendation”, which is wording that allows them to easily say no rather than write a weak letter that could doom your application. For people who only taught a class you did well in, there is no need to ask for a “strong” letter unless you had lots of interaction with them, and you can even explicitly tell them that you already have strong letters from people you worked with but need this additional letter to reach 3 letters.

In your email, include:

Letters of recommendation take time to write, and professors are often busy, so you should start months in advance to give them time, and make them aware of the deadline. Remind them one month before the deadline, then two weeks, and more as the deadline draws closer. This is not considered rude as long as you are polite.

One way to help your references keep track of what they have to do is to create an online spreadsheet with rows for references and columns for the places you need a letter for. You can then share this sheet with your references and ask them to put an ‘X’ in the corresponding cell when they’re done, which lets you track who did what and who needs reminding.

Always use an institutional email address for your references in the application form, such as a university email. If you use a private email such as, your application may be desk-rejected as nobody knows if the person uploading the letter is really the person you named as reference.

Writing a letter

Someone asked you for a letter of recommendation, and you want to help that person by following the expectations of schools like EPFL? Great!

Recommendation letters should provide useful and detailed information about the candidate, backed up with evidence. A short letter, especially one filled with platitudes such as “X is an enthusiastic and quick learner, and I enjoyed working with them, they would be a great fit for your program”, is useless. It’s typically better to reject a request than to write a letter that cannot support the candidate. Assessing a candidate’s skills requires honesty, and presenting a candidate’s weaknesses requires tact. Lying is never a good idea. If someone is found to have lied, for instance after a committee meets the candidate in person, or after people read different letters written over the years that contradict each other, nobody will believe the writer’s future letters.

Letters typically start by presenting the candidate and explaining how and how well the writer knows the candidate, with an immediate summary of the recommendation, including the specific position the letter is recommending for.

Readers will wonder if the writer would themselves make an offer to the candidate, so you must either explicitly state that you will do so, or explain why you cannot, which could be due to funding, a decision by the candidate to change locations, or plenty of other good reasons. Not stating anything will be interpreted as a negative: why are you recommending someone you wouldn’t hire yourself?

A summary of the writer’s qualifications helps the reader understand where the writer is coming from. For instance, if the writer has a degree from an institution comparable to where the candidate is applying to, and works in a field close to what the candidate wants to do, readers will put more weight on the recommendation. However, this part should not be overly long, as the focus of the letter is the candidate.

Readers expect a list the candidate’s strengths, justified with detailed explanations. For instance, if the candidate worked on a specific project, the letter should detail what happened and why it reflects well on the candidate. Descriptions that sets the candidate apart from others are especially useful. Did they achieve results others couldn’t? Were they particularly active in meetings? Did they go the extra mile on their own initiative? Do other members of the research group go to the candidate for advice on writing, or presentation, or any other skill? This part can be long if necessary. It’s perfectly acceptable for the letter to use more than one page. Readers expect evidence of all claims about the candidate, so letters should give clear examples.

It is helpful for readers if the letter explicitly compares the candidate with others, especially if there are specifics. For instance, a letter can compare the candidate with past students who went to the kind of institutions the candidate is applying to, with the letter writer, or with someone famous in the field.

If the candidate is not a native English speaker and the letter writer is in a position to judge the candidate’s English skills, readers will appreciate a short evaluation. Even merely saying that meetings were conducted in English and the candidate’s English level was never an issue is better than no information.