The cover letter is an integral part of the submission process. It is the first document that the editor of a journal will read and is your way to argue why your work is important, novel, and should be published in the journal you are submitting to. A strong cover letter won't get your paper accepted, but a weak one can lead to the dreaded 'rejected without review' letter from the editor. However, despite the importance of the cover letter, it doesn't receive much attention in the training of students relative to products like grant proposals and manuscripts. Furthermore, typically only the corresponding author writes the cover letter, so junior scientists get little exposure to the strategy behind composing cover letters. Even for senior scientists, they may only write 3-4 cover letters a year, so practice is minimal.
I'm about to submit the first manuscript of my PhD, so writing cover letters has been on my mind for a little while now. To prepare for the submission, I've been gathering strategies for writing cover letters from several scientists and looking over the previous cover letters I've written. To collate this information for myself and to share it with others, I decided to write this blog post. Below, I split the cover letter into what I see as 'standard' sections and give some commentary about of each of those sections.
The Header - This should be a typical letter head: the date the letter was written and an address to the editor in chief of the journal. This may seem pretty obvious, but when I wrote my first cover letter I was pretty confused about who to address the cover letter to.
The First Sentence (Formalities) - This seems pretty standard and formulaic. Something like: 'Please find enclosed a copy of our manuscript entitled "NAME OF MANUSCRIPT" to consider for publication as a type of submission in name of journal.
The First Paragraph (The problem) - The first paragraph is a place for you to layout the problem that your manuscript addresses. As the editor is unlikely to be an expert in your specific field or topic, similar to grant proposal reviewers, you should keep the discussion as broad as possible and free of jargon. In laying out the problem, you should convince the editor that the problem your manuscript addresses is important and worth a spot in their journal. While you are writing, keep in mind the scope and aims of the journal you are submitting to.
The Second Paragraph (Your manuscript) - In the second paragraph, it's time to talk about your specific manuscript. How does it address the problem that you outlined in the first paragraph? What was your general approach and the resulting findings? Lastly, you should discuss why the insights provided by your manuscript are important and their potential impacts. You should keep this discussion broad; it should not be a reiteration of the abstract.
The Third Paragraph (Novelty, fit, and reach) - In the third paragraph, you argue for why your manuscript should be published in the journal to which you are submitting. I usually do this, and have seen this done, in a three step process: 1) how the work is novel in the context of what has been published, 2) who will be interested in the manuscript and why, 3) how steps 1 and 2 lead to your manuscript fitting the aims and scope of the journal. Making your case for journal fit is important as I've heard that the number one reason for rejections without review is a mismatch between manuscripts and journal scope.
The Fourth Paragraph (More formalities) - Now its time to spout a bunch of things that the journal requires from you. This might seem pretty easy, but some parts of the process can be a little confusing. Some pieces are straight forward, you'll have to include a statement that all authors agree to the submission of the manuscript, that it isn't under consideration at any other journal, and that the data haven't been published elsewhere. The last part is one that can be pretty confusing. For example, the manuscript I am working on reanalyzes two published data sets. But the paper is about a new statistical method, so the fact that the data have already been published isn't a violation. Other cases might be a little more tricky. If you are really unsure about your submission, you should email the editor of the journal. Lastly, it's important to check the author guidelines of the specific journal you are submitting to as some journals require certain statements in the cover letter that others don't.
The Final Sentence (A thank you) - I like to end with a thank you to the editor for considering the manuscript. Editors are busy and have a tough job, so why not give them a thanks.
Signature - This should be straight-forward, but I've still seen some variation. Some people list all of the authors on the signature, some give their name and say 'on behalf of other authors', and others put only their own name. I'm partial to the latter since you've already written a statement that the other authors have agreed to the submission and the editor will see the other authors' names on the actual manuscript.
Suggested Reviewers - After the signature, I usually list 4-6 reviewers that I think are appropriate for the paper. Some journals will have online fields to put this information, so it may be redundant to place it in the cover letter.
I hope that this blog post will help other junior scientists to write strong cover letters for their manuscripts and get rid of some of the confusion that stems from inexperience writing cover letters. I'm sure that alternative strategies exist for writing cover letters, but I think the formula I provide above is one that works. Any comments on cover letters and the journal submission process are welcome in the comments section and I'd love to hear some other people's tips. I might post my own cover letter for my upcoming submission when the process is over and if there is any interest.