"Common knowledge" usually refers to...
facts and information that most people already know or could easily look up. According
to the sixth edition of the Little, Brown Reader, "Common knowledge consists of the
standard information of a field of study as well as folk literature and commonsense
observations" (547). Little, Brown continues: "You may treat common knowledge as your own, even if you have to look
it up in a reference book" (547).
When do you document?
In general, you don't need to acknowledge ideas, experiences, or results if they are drawn from your own experience. You do need to explain how you reached your conclusions and demonstrate the basis of your assertions.
Major facts of history, standard formulas/equations, and authors of works are generally considered common knowledge.
The date of Bill Clinton's election is common knowledge, but the notion that he was elected as a result of a generational split is not and should be documented and supported.
Little, Brown also talks about "commonsense observations," notions that most people would hold true.
Most people would agree that national politics often impact on local events; a statement like this doesn't need to be documented. But if you say something like "The New Federalism promoted by Bill Clinton is really an old form of socialist politics," you need to document the source of this insight.
- Always document information that is not your own or common knowledge.
- When in doubt, document.