Apply the following evaluation criteria to all types of information (print, broadcast, and online).
Identify the author(s) and whether they are experts in their field.
You may need to check biographical sources, to see that your author is a recognized authority on the subject, such as Biography Index, Who's Who, or Contemporary Authors.
For web resources, identify the website's sponsor (university, company, organization, or individual).
Determine if the source contains a bibliography; this may indicate that the author incorporates research published by others.
Consider journalistic integrity: is the journalist credible? What is the news source publishing the article's reputation? In the case of news articles, journalists are not always experts. Regardless, they can still provide credible information. You should always evaluate the credentials and career of a journalist, and take a closer look at the news source that is publishing the information.
Current information is important, but currency means different things for different disciplines.
Consider context. Does the currency of the information impact the validity of your argument? Depending on your assignment, it may be better to use older resources. For example, if you are writing a history paper about World War II, using primary sources from the 1940s may be appropriate. Even though the sources are 50 years old, it can be useful in the context of your research.
Timeliness is especially important in the sciences and engineering. For example, if you are writing a paper about HIV treatment, a source from the 1990s will probably not be as good as a source from the past 3 years. Unless, of course, you are writing about the progress of treatments over three decades, in which case it would be appropriate to have both older and current sources.
What year was the work from your source produced?
For web resources, determine when the site was last updated. Also, check the links to see if they work properly. Broken links may indicate that the website hasn't been updated recently.
Note the source where the information appears. Is it published in a scholarly journal? Does it include a bibliography? Are sources appropriately cited in the text?
Is the book published by a university press or other reputable academic publisher?
Use reasonably presented information.
Does the source material appear accurate and balanced, or is it heavily biased in one direction or another? Does the language or tone seem unbiased and free of emotion? Are there spelling, grammar or typographical errors?
What is the purpose of the information? Is it to inform, teach, sell, entertain or persuade? Do the authors/sponsors make their intentions or purpose clear? Is the information fact, opinion or propaganda?
Make sure the level of information is appropriate for your research.
Is it directed at a specialized or general audience?
Does the information relate to what you want to know about?
Have you looked at a variety of sources before determining which one(s) you will use? It is important to look widely; do not settle on the first source you find. Sources at the top of a list of search results aren't guaranteed to be relevant for your topic and appropriate sources for you to use; you must determine for yourself how well a source relates to your topic and whether it's appropriate to use for your purposes.
For example, you may be required to find and cite scholarly articles for a paper. Just because something was published in a peer reviewed journal doesn't mean it's necessarily a scholarly article - it may be a letter to the editor, or a book review, or an editorial. Your job is to identify whether the article you found from a scholarly journal is a good fit for your assignment - if it is, for example, an editorial or a book review, then it is likely not appropriate for your purposes and you should find something else to work with.
Primary vs. Secondary:
Primary sources are sometimes required in your research. These are firsthand, or original records of events, that include survey results, poems, diaries, ethnographies, artwork, data sets, statistics, or case studies.
The secondary aspect of sources comes into play when there is interpretation, analysis, synthesis, and/or restatement of these same events or materials in order to explain them.