When is the cover letter important?
As I noted above, the purpose of the cover letter is to convince the editor that your research has merit and is worth publishing. The first relevant point to note is that the editor is unlikely to be an expert in your specific field of research, which is particularly true in higher-profile journals where editors also regularly reject manuscripts without sending them to review. The cover letter is therefore your opportunity to convince this editor that your manuscript will be of interest to the readers of their journal and worth sending to external experts for review. Typically, the more high-profile the journal, the more important the cover letter will be. However, I always consider the cover letter to be important as it allows me to communicate with the editor my perspective on the bigger picture that my work is trying to address.
Overview of the cover letter
It is really important to be clear that the cover letter is not in any way a rewritten abstract. It can have a relatively similar structure, which I discuss below, but it should focus on (i) being broader in its scope by putting more emphasis on the fit of the manuscript into the bigger picture, (ii) focus less on the details of the predictions/findings and instead highlight the key take home messages, and (iii) put more emphasis on the novelty of the research. The last point is about highlighting what aspect about this manuscript is most significant in the context of the existing literature or body of knowledge. This novelty can be because the manuscript reports a completely new discovery, the application of a new method, the testing of a question which a much larger (and therefore more reliable) dataset than previously used, the first test of an important theory, and other reasons. The cover letter is where you can make strong statements about this novelty—statements that are often frowned upon within the manuscripts themselves (e.g. ‘This is the first study to …’).
Components of the cover letter
The template for a cover letter is relatively simple. It usually consists of quite fixed opening and closing statements with a few relatively structured paragraphs in between them. Below I briefly outline my typical structure for a cover letter and discuss each component afterwards.
Thank you for considering the manuscript entitled “….” for publication in [journal name]. In this manuscript, we provide evidence for …1
There is substantial interest in the question of …2
In this paper, we …3
Our study provides …4
We confirm that this manuscript has not been published elsewhere and is not under consideration by another journal. All authors have approved the manuscript and agree its submission. We declare no conflicts of interest...5
The first paragraph 1:
The first paragraph typically contains only 2 sentences. The first states your intent to submit a manuscript with a given title to the target journal. The second sentence can then be used to provide the 1-sentence take home message of the paper.
The second paragraph 2:
The second paragraph provides the background knowledge necessary for the editor to understand the broader perspective of this work. This includes highlighting key theories, outstanding questions, major omissions in the field, or areas that others have recently highlighted as priorities for research. It is basically a summary of your introduction in 3-4 sentences, clearly highlighting why the research gap exists.
The third paragraph 3:
The third paragraph is a clear statement of what the manuscript achieves. It gives a plain language summary of the broad approach used to address the gap highlighted in the previous paragraph. This should be concise and focus on providing enough to convince the editor that the methods, and therefore the evidence, are sufficiently robust.
The fourth paragraph 4:
The fourth paragraph is a relatively short statement of the new state of the field after your findings have been published—or how your work has advanced current knowledge. This is often followed with a statement about why your work would be of interest to the readership of the journal, which can include highlighting work published in that journal upon which your manuscript builds.
The fifth paragraph 5:
The end of the cover letter should include statements declaring that the authors have agreed to the submission and any conflicts of interest. It could also include a list of suitable reviewers.
One consideration is whether to reference existing literature or not. A cover letter should not be a literature review, and most of the time will not actually cite any specific papers. However, it is sometimes necessary or helpful to cite one or a few papers. These can include papers that make a very specific prediction, or outline a specific theory, that is being tested. Another can be to cite a recent review or influential study that has highlighted the gap that the research is filling.
Ideally, the cover letter should also be on the letter head of the primary institution of the corresponding author. Doing so provides a lot of legitimacy and adds a professional touch to the submission.
The higher-impact the journal the more important the cover letter will be. But don’t underestimate its importance elsewhere! It is often the first thing the editor will open, and could influence how they later perceive your research. Writing proper cover letters is also good practice, and writing about the broader context of the work can help to illuminate a better perspective on the manuscript’s findings. I have often found myself going back and updating my manuscript after writing the cover letter. So, the cover letter isn’t only important for getting editors to consider the manuscript, but also helps to act as a final check that the paper has a clear narrative.