Sensational: Overtly biased or provocative, these sources aim to peak the reader's interest regardless of facts. Thus the aim is to entertain more so than to inform. These sources are written by staff or freelance writers, and are aimed at a very general (and not-well educated) audience. Examples: Weekly World News, U.S. Weekly, People
Popular: These sources share facts and opinion about current news. They are written by staff or freelance writers and targeted to a general audience. They often claim objectivity and may point to more scholarly research, but sources are rarely or only occasionally cited. The main goals are to inform and entertain in pretty much equal portion. Articles are typically approved by an editor or at times, an editorial board.
Examples: New York Times, Newsweek, Time
Substantive: These also share the aims of informing and entertaining, but there is a greater emphasis on informing compared to the popular genre. Substantive works are written by staff writers or experts in the field, and the intended audience is the reader with some disciplinary interest and knowledge. These works tend to be more objective than popular writings and some sources are usually cited. Articles are typically approved by an editorial board. Examples: Popular Mechanics, Scientific American
Trade or Professional: These sources are written for a discipline- or profession-specific audience, and are written by expert scholars or professionals in a given field. They are aimed at other experts and professionals in that field and often use more scholarly, discipline-specific language, but the writing is typically more accessible than the writing in scholarly sources. These sources may describe new research being done, collect and reflect upon research published elsewhere, or report on direct professional practice techniques or issues. While written by scholars or professionals, and typically reviewed by other scholars or professionals, these sources are NOT peer-reviewed.
Examples: Journal of Social Work Education, Dissertations, Theses, Conference Proceedings
Scholarly: Scholarly publications are considered the most authoritative type of source because they have undergone a rigorous peer review process. Scholarly sources are written by expert scholars in the field, reviewed by other expert scholars in the field, and meant to be read by other scholars in that same field. Scholarly journals often publish original research, although they may often contain other types of articles such as literature reviews or meta-analysis.
Examples: Science, Nature, Journal of the American Medical Association
Ulrich's Periodical Directory provides a quick and definitive way to check whether or not a publication is peer reviewed. Peer review is also called "Refereed." If you enter your title and you see a referee's jersey icon:
You can tell that the research published in this journal is peer reviewed.