Citations not only locate a piece of writing within the context of a particular scholarly debate, they also allow writers to make claims based on the authority of another expert.
When do you need to use citations?
When quoting
When paraphrasing someone else's ideas
When using a statistic or direct fact
When you are using someone else's work as a theoretical
framework / interpretive lens
When you are relying upon data collected by someone else
When you are relying upon opinions or interpretations articulated by someone else
It will strengthen your case if you support any key assertions with citations
to show support amongst experts for accepting the validity of those assertions
When do you not need to use citations?
When stating common knowledge (knowledge that can be found in many
sources OTHER than those in the bibliography). If you aren't sure that something is common knowledge,
it probably isn't.
When the ideas, opinions, interpretations are your own, (although it
strengthens your case if you are able to cite others who would agree with you or whose work leads to
similar conclusions).
Two examples
A scientist researching the possibility of AIDS vaccines may rely on some data gathered by the Center
for Disease Control. Using a citation, the scientist tells the reader where the data was collected and
that the authority of the CDC attests to its accuracy.
Similarly in the Humanities, a scholar analyzing Jane Austen's Pride and Prejudice may cite a philosopher
or literary critic, like Michel Foucault. The scholar therefore identifies the type of interpretive lens
/ theoretical framework being brought to the analysis. Critics may or may not accept the validity of the
interpretive lens, but the scholar won't have to re-create the entire philosophy.