When evaluating a source, ask yourself if the source has a clear purpose. As the Purpose and Audience in Informative Writing lesson teaches, one of the keys to effective writing is a clearly-defined purpose. Closely tied to this is the need for supporting details that match with that purpose. Look for these as you evaluate a source.

What is the purpose of the information?

To determine the credibility of a source, determine if the purpose of that source matches with your own intended purpose. As mentioned in the previous section on source accuracy, if the purpose of your writing is to simply inform, you probably shouldn’t support your thesis with source material that has a clear purpose of entertaining or persuading. On the other hand, if your main purpose is to persuade, you’ll likely want to make sure you review not only source material with an informative purpose, but with a persuasive purpose as well.

Is that purpose clear?

At some point during your research, you may come across a source with no clear purpose. Perhaps it will lack a clear focus or thesis statement or perhaps it will have a seemingly clear focus, but then move away from it by the end of the article. If the purpose of a piece of source material you are evaluating is hard to find or appears to change, it’s likely a good indicator that this particular source is not as reliable as it could be. It would be wise to move on and find something that better matches your own purpose.