How to review a scientific paper.

Scientific observations must survive the scrutiny of experts before they are disseminated to the broader community because their publication in a scientific journal provides a stamp of validity. Although critical review of a manuscript by peers prior to publication in a scientific journal is a central element in this process, virtually no formal guidance is provided to reviewers about the nature of the task. In this article, the essence of peer review is described and critical steps in the process are summarized. The role of the peer reviewer as an intermediary and arbiter in the process of scientific communication between the authors and the readers via the vehicle of the particular journal is discussed and the responsibilities of the reviewer to each of the three parties (the author/s, readers, and the Journal editor) are defined. The two formal products of this activity are separate sets of reviewer comments to the editor and the authors and these are described. Ethical aspects of the process are considered and rewards accruing to the reviewer summarized.