The criteria for evaluating sources are just guidelines to help you think critically about the information you find. Depending upon how you are using the information, some criteria may be more useful than others:

• For finding just a few facts, accuracy is more important than relevance.
  
  
• Reading a book that's out of date can still add to your understanding of a subject, especially if the author is often cited as an expert or if your topic is in a field that doesn't change quickly, like the humanities.
  
  
• A biased source can contribute relevant facts and data. The National Rifle Association compiles plenty of data to promote its agenda. It’s your job to support or refute the arguments of impartial authors.