The RADAR framework is a system for heping students evaluate the relevance, reliability, and quality of any resource.
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?
Authority
Is the author known as an 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?
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?
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?
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.
More about the RADAR method
See: J. Mandalios, “RADAR: An approach for helping students evaluate Internet sources,” J. Inf. Sci., Vol. 39, no. 4, pp. 470-478, 2013.