Peer review is a mechanism by which the research community asserts quality control. It has become an essential feature of the decision-making processe used by most funding agencies and all respected journals. A feature common to all peer reviews is that they are performed by one or more individuals active in a field of study that is central to the item being reviewed.

When a paper is submitted to a peer-reviewed journal for publication, it is usually given to a topical editor. That editor maintains a list of active researchers and their areas of expertise. This list is often assembled from authors who have previously published in the journal and referred to a peer review list. The paper is sent out to one to three of those peer reviewers. After reading the paper, a reviewer returns it with comments and an overall conclusion, typically of this form:

The editor makes the final decision, based on the recommendations of the reviewer(s). In the case of unfavorable review, most journals allow for some sort of an appeal process that often involves sending the paper to another peer reviewer.

When a grant proposal is sent to a funding agency, there are a number of ways in which peer review may enter into the decision-making process. An individual proposal is often sent out for an ad hoc peer review by a few individual reviewers. In other cases, reviewers are brought together as to review a number of proposals. This group of peers takes a collective look at all of the applications. The program officer from the funding agency may also act as a peer reviewer. The National Science Foundation, for instance, makes a point of hiring active researchers for short periods of time (a year or two) to serve as program officials through their Visiting Scientist, Engineer, and Educator Program. Anonymous reviewer comments for federal proposals are always available to proposal writers who are not funded.

One feature that varies from process to process is the degree of anonymity. In some situations, the author (of the proposal or paper) does not know the identity of the peer reviewers, and the reviewers do not know the identity of the author. This is known as double blind peer review. In single blind peer review, the reviewers know the name of the author, but the author is not told the names of the reviewers. In unblinded peer review, the names are not shielded. Single blind peer review is the most common. The philosophy behind this procedure is that reviewers can be freer to speak their minds without any external pressure if they remain anonymous. Proponents of unblinded review, however, argue that reviews are likely to be of higher quality if reviewers are obligated to sign the reviews-there will be fewer instances of either sloppy reviews or mean-spirited reviews. At the other end of the spectrum, the double blind review seeks to remove bias from the process by shielding the authors' names from the reviewers. In some cases, however, it is easy to guess the identity of the authors based on their writing style, their citation list, etc.

The goal of the peer review process is to help improve the quality of the research that is funded and the papers that appear in print. To the extent the process has improved quality, all active participants in the field have benefited from it. The peer review process has broader implications, too. By improving the quality of the published literature and by improving the effectiveness with which public funds are used, peer review helps to increase the confidence society at large has in the scientific community. It is reasonable then to conclude that all active participants have an obligation to contribute to the peer review process. In most cases, it is a volunteer process, and it can be time consuming, but it is an essential part of progress in the field.

The peer review process can be misused. For instance, it is possible to twist its goals to use it to gain a competitive advantage in research. Being sloppy with one's responsibility about how the review is carried out can possibly cause unintentional harm to others. What follows is a discussion of key policies and ethical principles related to peer review.