It includes original research, also called primary literature, that reports new research. In scientific disciplines, original reserch is most often published as an article in a scholarly journal.
Article reports data.
Articles are peer-reviewed, they are read and reviewed by other scholars in the field before publication. Popular literature may be reviewed by an editor, working for the publication before it is released to the public, but it is not carefully reviewed by a group of peer-scholars. Secondary literature includes literature reviews, popular periodical publications, indexes and abstracts, reference works, among many others. These materials synthesize and repackage, or point researcher to, primary research. Articles published in popular periodicals such as Scientific American , Psychology Today , and news magazines are examples of this type of literature because they may refer to a scholarly article published in a scientific journal.