The research process does not always follow a straight path. You may even find yourself changing your argument in the final stages of writing. Sometimes you will not find the sources or answers you expect to on the first try.
Before you read a source or spend time hunting for it, begin by asking yourself the following questions to evaluate it:
Is the subject what you expected?
If not, reexamine the keywords you are using. Look at the results that seem closest to your topic to see what subject headings are used to describe the article or book.
Are you the intended audience?
Consider the tone, style, level of information, and assumptions the author makes about the reader. If not, reconsider the database or index you are searching.