Peer Review Process

Peer review is a process whereby experts help judge the value of a work that they were not part of creating. Editorial peer review involves scientific or academic manuscripts submitted for publication or meeting presentation, while grant peer review involves review of funding applications. This entry focuses on editorial peer review of work submitted to scientific journals, although some of the issues discussed apply to other types of peer review as well. The primary function of editorial peer review is gate-keeping—selecting the best from a pool of submissions. In addition, peer review often involves constructive criticisms intended to improve a submitted work prior to publication. A common misunderstanding is that peer review validates the scientific integrity of a published article. Expecting such validation is unrealistic, as reviewers typically have access only to what the author or authors present in the manuscript. Important logistical and methodological decisions made along the way will be unknown to the reviewers, as will key details that the authors might omit. In essence, we must trust the authors.

Early forms of editorial peer review go back as far as the beginning of the 18th century, most notably within the Royal Societies of London and Edinburgh. The first modern peer review system was developed in the late 19th century by Ernest Hart, editor of the British Medical Journal. Yet it was only after World War II, as medical research methods became more sophisticated and journals became more selective, that peer review systems became institutionalized in the scientific and academic journals of the United Kingdom, the United States, and elsewhere.

In this context, the term peer is loosely interpreted to include subject-area experts, statisticians and methodologists, journal editors, editorial boards, and sometimes others, such as graduate students or nonexperts. Outside experts are usually sought because of their specialized knowledge in the submitted manuscript's content area or their advanced statistical or methodological skills. Ideally, these reviewers will have more expertise than the authors of the submitted work. But because of the proliferation of scientific journals and the many competing demands on experts’ time, this specialized ideal is not always reached. It is therefore not uncommon for less qualified reviewers to assume this role.

A variety of peer review systems are employed across the world's 10,000 or so journals. Systems vary in their relative reliance on external reviewers, such as outside experts, versus in-house reviewers, such as editors and editorial boards. Acceptance rates can differ widely across journals, ranging from around 2% for the most highly selective journals to 90% and above for some electronic journals where publication space is less of an issue, and pay-per-page journals such as those that serve primarily as outlets for routine pharmaceutical studies.

Postpublication peer review is an important, if often neglected, type of review. This can include letters to the editor or full articles critiquing a published work, sometimes going so far as to involve reanalysis of the original data. While the need for postpublication review is now receiving more attention, challenges remain. Authors sometimes choose to ignore a published critique or respond minimally to peripheral issues in place of the specific criticisms made. Even when serious errors are detailed in a critique, retractions or corrections are the exception. Medline and other databases rarely link postpublication critiques to the original article, and literature reviews that cite a criticized work frequently ignore the critique.

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