The purpose of peer review is to improve the quality of the manuscript under review and the final published material. Conscientious peer review is a time-consuming task, but it is essential to ensure the quality of scientific journals. Chronobiology in Medicine is very grateful for the time and effort you contribute in the review process. Chronobiology of Medicine adheres to the Publication Ethics Committee (COPE) Code of Conduct and Best Practice Guidelines (http://publicationethics.org). We endeavor to ensure peer review is fair and unbiased and timely. The decision to accept or reject a manuscript is based on the manuscript's importance, originality and clarity, the validity of the study, and its relevance to journal. We use a wide range of sources to identify potential reviewers, including editorial boards, personal knowledge, author suggestions, and bibliographic databases. The reviewer's evaluation plays an important role in our decision on whether to accept the manuscript for publication. Chronobiology of Medicine operates a single-blind review process that hides the reviewer's identity to the author.

General Issues

The review should be carried out fairly and objectively. Personal criticism of the author is inappropriate. If the research reported in the manuscript is flawed, criticize science, not scientists. Personal criticism can cause authors to ignore useful comments, making your reviews less useful in your field. Criticism should be objective, not just a disagreement, and help authors improve their papers. You should decline to review manuscripts that have a conflict of interest due to competition, cooperation or other relationship or connection with the author, companies or institutions linked to the article. If your previous or current connection with the author(s) or author's institution might be construed as causing a conflict of interest, please include this issue in a confidential comment to the. If in doubt, please contact the editor who requested the review before accepting. Respect the confidentiality of the manuscript sent to you. Do not discuss unpublished manuscripts with colleagues or use information in your work. If you think a colleague is more qualified than reviewing a paper, do not forward the manuscript to that person without first asking the editor for permission. Reviews and recommendations should also be considered confidential.

Comments to the Editor

Your Comments to the Editor will only be submitted to the Editor-in-Chief. These should include any possible conflict of interest. Opinion and constructive criticism of the manuscript should be included in the Comments to the Author.

Comments to the Author

Your Comments on the Author will be submitted to the Editor-in-Chief. The EIC is communicated to the authors and to the other anonymous reviewers of the manuscript once the editor has made a decision. Comments should be constructive and designed to improve the manuscript. You should think of yourself as the mentor of the author. Make your comments as complete and detailed as possible. Clearly express your opinion by providing arguments and references as needed. Include clear comments about the strengths, weaknesses and relevance of the manuscript, its originality and the importance of the field. Specific comments that cite line numbers are most helpful. If you believe that you are not eligible to cover a particular aspect of the manuscript, please include a description to identify that area. Identify the major contributions of the paper at first. What are its main strengths and weaknesses? Include both general and specific comments about these questions, and highlight the most important points. Support your general comments, positive or negative, with specific evidence. You may also upload other documents (e.g. your review as a document, useful references).

Here are some points to consider when reviewing:
- Is the topic of the manuscript appropriate for the journal? Is there information that is important to a broad readership of the journal?
- Do titles, abstracts, keywords, introduction, and conclusions accurately and consistently reflect the main points of the paper?
- Is the aim clearly stated?
- Is writing concise, easily to follow, and without repetition?
- Are the methods appropriate, scientifically sound, up-to-date and clearly described so that others can repeat the work?
- Consider the length of the manuscript in relation to the contents.
- Is the research ethical and appropriately approved/consent been obtained?
- Are appropriate statistical analyses used? Are they justified and explained enough? Is the statement of importance justified?
- When the results are mentioned in the text of the paper, are they supported by the data? Is it easy to verify the tables and the figures?
- Are all tables and the figures needed, clearly labelled, well designed, and easy to interpret? Are there duplicate information in tables and figures? Is it repeated in the text?
- Are the conclusions supported by the data presented?
- Does the manuscript comply with the Instructions for Authors?
- Are the references most appropriate to support the manuscript? Are citations provided for all assertions of fact not supported by the data in this paper? Are there any important citations missing?

Please also comment on any possible misconduct, such as:
- Does this manuscript report data already published or in press? If so, please provide details.
- Did the author plagiarize other publications?
- Is there an indication that the data has been fabricated or inappropriately manipulated?
- Did the author declare all relevant competing interests?