This is another form of plagiarism that is often unintentional. As you’ll have already realised, it’s important to acknowledge your sources of information in your work, but in a subject field there are well-known and established facts and knowledge which do not need acknowledgement. If you’re new to a subject it can be difficult to work out what this kind of common knowledge is.
Common knowledge is generally accepted as being information that is:
- well known to all in a particular field
- easily verified by consulting standard textbooks or encyclopaedias
- not disputed
- undisputed historical facts
- known formulae or equations
If you are unsure whether a piece of information, theory or methodology you want to use in your work is common knowledge, be safe by including a reference to the source you read. Ask your lecturer or tutor, as they will be able to tell you if what you’ve read is common knowledge. You will find that as your subject knowledge develops, so will your awareness of what is and isn’t common knowledge.
Some examples of common knowledge:
π = 3.1416
H2O = water
Common knowledge changes over time. If you had described the structure of DNA fifty years ago you would have had to acknowledge your source. Today it is accepted as common knowledge. In fifty years time the number of human genes will be common knowledge.
A good way of establishing common knowledge is by looking for references to the information you read in textbooks. If a particular fact or theory is not acknowledged by a textbook author, then it’s likely that this is common knowledge. But as we said above, if you’re not sure, check with your lecturer, or include an acknowledgement.