Authority: Who wrote the article or book? What qualifies that author to be an authority on the subject? Does s/he have credentials that can be verified? (Read about John Gray, the author of Men are from Mars, Women are from Venus, and Columbia Pacific University for an example.) If the author does not have educational credentials, what experiences has s/he had that qualifies her to speak about that topic? Can those experiences be verified? (Read The Smoking Gun's report about James Frey, the author of A Million Little Pieces for an example.)

Objectivity: Supposing that the author is an authority on the subject, does he have a vested interest in the issue that may cause the information in your source to be biased? Does the source provide opposing viewpoints so that more than one position on the issue may be understood by the reader, or does it endorse one position without acknowledging opposing viewpoints?

Variety: Does the source incorporate multiple sources of information to discuss its topic? (Check the bibliography to see.)

Age: When was the source published? Newer, more accurate information may be available if the source is a few years old.

Validity & Reliability: If your are reading about results of a research study, were the results derived from research methods that were valid (methods that measure what they're supposed to measure) and reliable (methods that measure the same thing the same way every single time). Validity and reliability of research methods can be crucial to how seriously the conclusions of the study should be taken. Always look for information about sample sizes (larger is better), and be wary of studies that don't report them.