What is Peer Review?
Peer review refers to the very specific formalized process that academic journals put submitted articles through before publication. The peer review process investigates the article's quality, accuracy, and relevancy. Articles are reviewed by a panel of experts in the subject field and are either approved by the panel or not approved. If approved, the editor of the journal then makes the final decision whether to publish the article in the journal or not. If they are not approved, they are not considered for publication.
While other types of information (like newspapers, encyclopedias, nonfiction books) go through their own review or editing process, they do not go through the specific peer review process. Academic journal articles are the only types of information that are held to this standard.
Peer review is a rigorous process that can take months, and articles have to meet a long list of criteria before they can be considered for publication. This is why peer reviewed materials are considered the most trustworthy for your research.
Watch the below short video (3:15 minutes), made by the North Caroline State University Libraries, for more information about peer review.