When you are conducting research you will most likely come across the term "peer reviewed." This phrase indicates that the research article in question has gone through the peer review process, a rigorous review process designed to weed out poor quality research. An article that goes through this process is first submitted to a journal, which then sends the article to several experts in their field who have agreed to serve as reviewers--thus the article is reviewed by the researcher's peers. The reviewers then send their comments back to the journal, who passes them along to the researcher. In most cases the whole process is anonymous to reduce bias. The reviewers can recommend edits or revisions to the article that must be completed before the article is accepted for publication, or the article can be accepted or rejected with no revisions.
The reviewers evaluate all aspects of both the article and the research itself, including methodology, quality of the literature review, the results and conclusions, and the overall writing quality and organization. This review process helps to prevent the publication of articles that contain poor or even fabricated research and/or conclusions. For example, if a research article reports reasonable and valid findings but then makes wild and unsubstantiated claims about what those results mean, the peer reviewers will most likely reject the article or recommend extensive revision before publication. As you can imagine, this review process makes it much harder and more competitive for researchers to publish their work in peer reviewed journals, and therefore you can be more confident in the quality of the research that makes it into these journals. Articles that are published without going through this review process are much more likely to be of poor quality than those that are reviewed.
Keep in mind that "peer reviewed" or "scholarly" might be interpreted slightly differently in different disciplines. Peer review is extremely important in the sciences and social sciences, whereas the arts and humanities may place less emphasis on the distinction. Be aware of the standards and expectations for your field when conducting research.
More or less. There are some subtle differences. "Scholarly" or "academic" generally signifies that the source would be acceptable in a research paper or a project for class. "Peer-reviewed" and "refereed" specifically mean that the source has been vetted by experts. However, if you're searching for articles in databases, most databases tend to use these terms interchangeably.
Absolutely not! Many good sources of information have not been peer-reviewed. It may vary depending on field. Peer review is extremely important in the sciences and social sciences, whereas the arts and humanities may place less emphasis on the distinction.
It may also vary depending on the type of source. For example, newspapers are not peer-reviewed since they are published too quickly to be vetted by reviewers. On the flip side, the review/editing process for books is different since they can be hundreds of pages long and take longer to be published.
Make sure you're aware of the standards and expectations for reputable sources in your field, and that you follow your assignment guidelines.
