In your literature research, you may find many types of information sources including journal articles, conference papers, books and web pages from a variety of information resources. You need to evaluate how appropriate and reliable these sources/resources are used for your research. In addition, you should search and read broadly in a subject area to develop a comprehensive understanding of your research topic, and try to identify highly relevant and credible sources for your literature review.
RADAR is an acronym representing a framework for evaluating information sources, to determine whether or not they are appropriate for your research.
R is for Relevance: Does the source relate to your topic or answer your research question? Does it meet the requirements for the assignment? Have you looked at a variety of sources before determining this is the one you will use?
A is for Authority: Is the author known as expert in the field? Does the author work for a reputable institution, e.g. a university, research center or government? Does anyone cite this author/work? Does the author rely on other well-cited works? Is there contact information, e.g. a publisher or email address?
D is for Date: Has the information been revised or updated? Does your topic require current information, or will older sources work as well? If older, is this a seminal or landmark work? Are the links functional?
A is also for Appearance: Was the work published by a peer-reviewed journal, academic press or other reliable publisher? Was the information reviewed by an editor or a subject expert before it was published? Do the references support the author's argument? Are the references properly cited? Can you verify any of the information in another source? Does the source look professional? Are there advertisements, typographical errors, or biased language?
R is also for Reason: Why was the information created? Appropriate information sources are created: to educate by spreading scholarly information; sometimes but not always to persuade the reader; never to entertain or sell something.
Mandalios, J. (2013). RADAR: An approach for helping students evaluate Internet sources. Journal of Information Science, 39(4), 470-478.