To complement a blog post on asking for letters of recommendation, the MIT Communication Lab hereby shares general tips on writing letters of recommendation. Use this guide if you were asked to write a letter of recommendation and are looking for general tips on how to write the strongest letter. If you are the seeker of letters of recommendation, don’t start here! It is essential for you to visit our companion blog post before learning more about writing letters of recommendation.

Writing a letter of recommendation is an important responsibility, consequential both in your own career and credibility (the mentor) and in the requester’s future (the mentee). A well-crafted letter takes time and requires some reflection on your relationship with the person you are recommending. Here are some tips to write an influential letter of recommendation.

Note/disclaimer: This article is not tailored to serve experienced letter writers but instead hopes to constitute a solid foundation to orient and reassure junior writers (for instance those asked to write a letter in support of an undergraduate student applying to graduate / medical school or to a first job). The guidelines shared below are not fast rules nor do they indicate a structure expected in MIT Biological Engineering applications; in time, you will develop your own style and perhaps your own recipe, as you read more letters yourself and recognize perspectives and phrases that resonate with you. This guide is meant to serve as a generic guide to help letter writers advocate successfully for the students they are recommending.

Remember that you can make an appointment with the Communication Lab to brainstorm what to include in your letter, or to review and edit your draft. We have annotated a recommendation letter to identify the important components. You can also find more examples of recommendation letters on this website.

  • Define the scope of your letter by understanding from your mentee who else they’re collecting letters from and, if possible, by explicitly hearing from your mentee what particular traits or strengths they are hoping you’ll address in your letter. The mentee should carefully select a balanced set of letter writers who can collectively testify to all the qualifications the mentee wishes to put forth. It’s also in the mentee’s best interest to inform you of their overall statement of purpose, so you can align your message with theirs.
  • Be very explicit and honest about your level of support and enthusiasm for the mentee’s application, in your first and last paragraphs.
    • Be emphatic about stellar mentees (with phrases like “my absolute strongest recommendation”, “I would have the student join my lab if they applied”), but more modestly excited for more average mentees (“I believe they can be successful in your program”). Committees may read several of your letters over the years, and you want your word, your “support knob”, to be trustworthy and well-calibrated to reflect faithfully your assessment of the mentees’ capabilities.
    • It may happen that your readers know you personally and may be able to detect the genuineness of your tone throughout the letter. Consequently, even if someone writes a first draft of the letter for you (it is indeed common for professionals in high positions to delegate the bulk of the writing to colleagues who worked more closely with the mentee), take time to revise it and use your own natural “voice”, so your readers can recognize and interpret it.
    • In many institutions, a record is kept of all of your past letters, 20 years back! Be as accurate as you can when comparing mentees in consecutive years.
    • Acceptance to top programs is extremely competitive and these programs often receive many applications whose references describe candidates as “truly outstanding”, “exceptional”, “best in 5 years” and the like. Consider including informative comparative statements both to the candidates’ peer comparison set during their past training as well as acceptees of the program the candidate is applying for (to the best of your knowledge). Specific comments about the candidate’s potential for future growth can be helpful, but may also be interpreted as indirect criticism of the candidate or an indication of the candidate’s existing weaknesses.
  • State your professional role and how you have interacted with the mentee early in your letter.
    • Especially if you are relatively junior in your field, it is also useful to briefly detail your background. Through this lens, you can indicate how many mentees you have observed and evaluated over the years, and how this letter’s mentee compares or ranks with their peers.
    • Be quantitative in your comparison if the numbers reflect positively on the mentee (e.g. “top 10%”, “best in 5 years”)
    • If former mentees of yours have been accepted to the coveted position, compare the candidate to this cohort.
    • It is worth mentioning if you yourself were once part of the sought-out organization, as readers will deem your judgment better informed and well-adjusted.
  • Be aware of implicit biases. These are great resources on how to avoid gender bias and racial bias (or “code words”) in letters of recommendation, but remember that implicit bias plays a role in how we write recommendations for many groups of people.
  • Gauge which three-to-four skills will be most important or best matched to the program the student is applying to, and dedicate one paragraph to each of these skills.
    • Try and recall situations when you have personally witnessed the mentee demonstrate these skills. Relate the mentee’s past experiences in a way that showcases these important competencies.
    • Include as many details as you remember, in order to make the mentee memorable to the readers, and to make your appraisal grounded and convincing.
    • Don’t overplay a student’s high grade point average (GPA). The GPA is considered to be a badge of reliability, a solid foundation for further meaningful achievements. Only choose to dwell on the GPA if any hiccups merit justification.
      • During the COVID-19 pandemic, most academic institutions implemented exceptional disruptions in order to keep students and employees safe. Your mentees’ transcripts and CVs are likely to reflect these arduous times and the decisions made to keep up engagement and productivity. When possible, attempt to “interpret” emergency grades (such as pass/fail) and provide insight as to which regular grade (for instance A or B) the performance amounted to. Strive to add context and nuance when explaining why your mentee may have switched projects, or found a remote or computational temporary tangent internship, removed from their traditional research setting. And of course, highlight qualities illustrated by the COVID parenthesis,  including your mentee’s inventiveness, determination, can-do attitude, professionalism, adaptability.
    • If you know the target organization closely, use your awareness of its core values to explain why the mentee would be a good fit.
      • Alternatively, if you are unfamiliar with the target organization, parse the organization’s webpage to gauge which skills and traits the organization values. Incorporate the language utilized by the organization to describe successful applicants and applications into your letter.
      • e.g., if an organization values “independent, self-driven students dedicated to service”, you can specifically describe how your mentee exhibits independence and the pursuit of service.
    • If the mentee is applying to graduate school for instance, highlighting the student’s familiarity with research settings is imperative. Illustrating their tenacity, perseverance, resourcefulness, and creativity in the face of inconclusive results or other adverse events will also underscore the preparedness of the student. Tangible accomplishments with a lasting impact on the research group, such as (but not exclusively) publications, are of great advantage too. Focus on a single project over many semesters, independence, patience, ability to rapidly learn new skills, and technical expertise are all qualities ideally embodied by aspiring graduate students.
    • Letters from academic instructors, rather than from research advisors, often serve as additional letters to recount the excellent classroom work the student produced. The student’s GPA speaks for itself and narrating “another A” will not make a marked difference in the student’s application. If you are an academic instructor, think of all the ways the student stands out and focus on making sure your reader is aware of those exceptional traits!
    • If the mentee is applying to medical school, speaking of their empathy, cultural competence, ethics, social and interpersonal talents, including communication skills, can be a significant complement to highlighting their intellectual and scientific chops.
    • To join a startup, a mentee would preferably not be risk-averse, be able to pivot and switch priorities, and be highly motivated to give work a large place in their overall lives.
    • Being a good team player is key in industry… and everywhere!
    • For industry, it is also certainly worth highlighting your mentee’s translational mindset; being able to work across disciplines (e.g. interfacing technically with scientists and concisely with businesspeople) is a valuable skillset.
    • Talk about extracurricular activities not as a laundry list or aiming at being comprehensive in your portrait of the mentee but only if they are an outstanding expression of the student’s leadership, passion, aspirations, motto…
    • Mentioning involvement in diversity, equity, and inclusion (DEI) endeavors can be viewed as a plus, but here again be very intentional in your writing: what specific qualities in the mentee are you intending to spotlight?
  • As you conclude your letter and reiterate your esteem for the mentee and the promise you see in them, mentioning the trust you have in the mentee’s entire career (not simply their first next step) can go a long way in persuading the readers of your honest confidence.
  • Some recommenders choose to bold words or sentences in their letters, in order to direct the reader’s eyes to essential contents in their paragraphs. This must be done carefully to be effective: often readers will skim the letter and only pay attention to its bolded parts, so a full picture of the student should transpire through this bolded summary.
  • Use institutional letterhead for your letter. MIT’s letterhead can be found here. Institutional identity helps contextualize your standpoint for readers.
  • Check whether the letter should be addressed to one person in particular, one committee by name, or should be very generic in its opening.

Get started with your own letter of recommendation! Find a quiet setting, reserve an uninterrupted block of time, and organize your thoughts about your mentee, their traits and accomplishments, and your relationship. A short, thoughtful letter is better than no letter at all! And remember, if you think you cannot in good conscience write a positive letter, alert your mentee right away, and decline kindly, so your mentee has time to turn around and make other arrangements before the deadline.


Blog post written by Maxine Jonas, Viraat Goel, and Prerna Bhargava.