What category of literature is described as professional literature that has not been peer reviewed?

Gray literature refers to a type of professional literature that is not formally published in traditional journals and has not undergone the rigorous peer review process typical of scholarly publications. This category includes a variety of documents such as reports, theses, conference proceedings, and government publications. The significance of gray literature lies in its ability to provide valuable insights, data, and information that may not be readily available in peer-reviewed journals, making it an essential resource for researchers and professionals in various fields.

Other document types mentioned, such as white papers, are specific types of gray literature that typically present authoritative reports or proposals on specific issues, but they may not represent the broader category of gray literature as a whole. Peer-reviewed literature, by contrast, is characterized by having undergone evaluation by experts in the field, ensuring a certain level of quality and reliability. Abstracts are brief summaries of a study or paper and do not represent a category of literature on their own. Thus, while white papers, peer-reviewed works, and abstracts each have their places in the literature, they do not encompass the full scope of what gray literature represents.