Written by Patrick Yachimski, MD, MPH from Vanderbilt University Medical Center.
A manuscript review, like any other form of written communication, is intended for the consumption of a reading audience. This is a basic premise, but one which is easily overlooked or taken for granted. Before authoring a manuscript review, it is well worth reminding oneself of the intended audience.
At a fundamental level, the review is written for the journal and its editor(s), who seek feedback on the quality of the manuscript, including its anticipated level of impact in the field and appropriateness for publication in the journal.
Of at least equal importance, however, is the fact that the review is also intended for the manuscript author(s), who have devoted considerable time and effort in completing research or scholarly endeavor and preparing the product of their work for submission. No one will read your review more closely than the author(s), and irrespective of the final editorial decision on the manuscript, no one stands to benefit more than the author(s) from your review. It is fair to be blunt and honest in your critique if the spirit is to help the author(s) improve the current manuscript as well as future work. Tone is important. One can politely question results or conclusions without being accusatory. Be very careful and very certain if you are to challenge that the manuscript contains statistical or factual inaccuracies as, unless the manuscript is invited for revisions and resubmission, the author(s) lack a forum to respond to such assertions.
A fair and thoughtful review will be of considerable value to your audience, editors and authors. And remember, the review is never for or about you. The review should not be viewed as an opportunity to dazzle or impress the editors with scathing commentary or insight. The review should not include subtle (or not so subtle) encouragement that the authors cite work which you have previously published. And a review that is just plain mean-spirited will reflect poorly not only on the journal but also on you, the reviewer.