Thanks to the University of Delaware Library for the infographic!
ARTICLES
Journals, magazines, and newspapers can be divided into four basic categories (ranked here from most reliable to least reliable):
1. Scholarly
2. General Interest / Substantive News
3. Popular
4. Sensational
Think about it - if you were preparing a presentation on political parties, would you trust The Journal of Political Science or the local supermarket tabloid with aliens from Mars on the cover? That's the difference between scholarly and sensational!
SCHOLARLY journals require articles to be reviewed by other experts or scholars in the same field (thus "peer reviewed") who must agree that the article in question meets the standards of that profession. This ensures that the content of the article is as valid and reliable as possible.
So how do you tell if a journal is scholarly?
(More information on the four basic categories can be found here!)
BOOKS
Books can be popular, scholarly, general interest, or sensational too. Books can be tricky, though, because they don't always make it clear if they're scholarly or not.
So think "APPLE".
Author - is the author an expert in his/her field?
Purpose - what kind of information is the book trying to convey?
Publisher - who made the book available?
Language - how sophisticated is the language used in the text?
Evidence - what sources does the author use to draw conclusions?
(This is just a brief list - for more on distinguishing a popular book from a scholarly book, go HERE!)