How to write a letter of recommendation: 5 essentials

I’ve written letters for these three great postdocs.

“Kind to pets” is what a colleague calls positive letters of recommendation that don’t really say anything. Even worse is “word salad,” a series of highly predictable sentences that could be said about anyone.  I write tons of letters every year and read hundreds more. What makes a letter good? What gets your student or your colleague the job, the prize, or admission to grad school? What if you have to write for several people from your group for the same job? This is both harder and easier than you think.

It must be hard because I have just read hundreds of letters of reference for the 3 open positions we have and generally each one has only a paragraph or two of real substance. Here are some guidelines I hope are helpful.  Generally, think about what we want to know. Think about how to make people come alive as individuals. I like to think that readers of fiction probably know better than others how to write a good letter. Show don’t tell. Remember that many of the letter readers do not know the field well, or even at all, so we need to be educated.

1. Begin with an overview. Let us know if this is a positive letter, an extremely positive letter, or the best letter you have written for anyone. You won’t necessarily rank them this way, but we will. The adjectives we will be looking for include smart, scholarly (reads the literature) creative, collegial, and productive. We would also like to know this person is an independent self-starter with grit. But saying this is not enough. The letter must back up your opinion with stories. Be careful to avoid sexism in your choice of adjectives.

In this first paragraph you can also tell us what general area the person works on. Don’t make this too long or too grandiose. A surprising number of the ecology candidates had letters that I could not tell at all what they did from these first words.

2. Tell us how you know the person. I prefer letters that do not give an overview of a person’s whole career, unless you know something special. Focus on your direct experience and let us know what and when it was. I avoid saying things like “last year” and instead put the actual year in, because last year goes out of date rapidly and chances are I will be writing for this person for years to come.

3. Tell us what this person has discovered and why it is important. This to me is one of the most crucial parts of the letter and yet many leave it out entirely. Do not tell me what area the person works in without telling me what they have discovered.  Why do so many people not do this? When you explain what they have discovered, remember that I am not in your field. I might not even be close to your field. You need to tell me in concrete terms what they discovered and also why it is important. Tell me that there was this problem in the field and no one knew the answer to this and then along came this candidate and did this amazing experiment/observation/analysis and all was solved, or advanced. This can take two or three paragraphs.

4. Make your person come alive with stories. Who is this person? What can you tell us about them that will make us like them, look forward to having them in our university, department, or program? Tell a couple of anecdotes that illustrate the wonderful characteristics of the person that you mentioned in the first paragraph. These perhaps more than anything are what we can grab onto and remember.

5. Tell us the special skills your person has. These days people like to hear your person has special tools at their command, whether it be experimental design, modeling, big datasets, genomics, GIS, microscopy or something else. Usually this does get mentioned and might even get over stressed, but don’t leave it out entirely. It can be built into a story also.

The whole letter is ideally only 2 single-spaced pages, though major professors can go longer for their students. A single page letter must be really pithy or we will view it as weak. Remember, the best letter will not necessarily get the person the job, but feeling like you know someone already from the vividness of the letter is a great start. And never, ever use the same letter entirely or partially for different people applying to the same job.