Standards for Evaluating Secondary Sources (Beyond Peer Review)
Does the author have a relevant academic or institutional affiliation? Has the author published other books or articles on the subject?
Why, and for whom, was the source written? Is the author an academic who is engaging in a particular scholarly conversation, or is this a personal response to an issue or text? Does the author have some kind of financial stake in expressing a particular point of view? Does the author work for an organization with a known viewpoint on the issues discussed in the source? It's important to make sure that you ask these questions so that you'll know whether a source is of limited use to you due to a bias or a particular perspective.
What does the source cover, and in what depth? Is the argument that it makes relevant to your topic? Does it lay out background information relevant to your topic or summarize other research?
Is the publication a peer-reviewed journal or a university press book? Is it published by an organization with a known viewpoint or financial stake in an issue? Articles and books published by organizations with political affiliations or financial interests may be useful to you as you learn about a topic, but you should be aware of how these affiliations and interests might shape the data or arguments in the source.
Depending on the field of study, it may be crucial to use the most up-to-date sources.
adapted from The Harvard Guide to Using Sources