What is common knowledge?
You may have heard people say that you do not have to cite your source when the information you include is “common knowledge.” But what is common knowledge?
Broadly speaking, common knowledge refers to information that the average, educated reader would accept as reliable without having to look it up. This includes:
- Information that most people know, such as that water freezes at 0 degrees Celsius or that Sir John A. Macdonald was the first Prime Minister of Canada.
- Information shared by a cultural or national group, such as the names of famous heroes or events in the nation’s history that are remembered and celebrated.
- Knowledge shared by members of a certain field, such as the fact that the necessary condition for diffraction of radiation of wavelength from a crystalline solid is given by Bragg’s law.
However, what may be common knowledge in one culture, nation, academic discipline or peer group may not be common knowledge in another.
How do I determine if the information I am using is common knowledge?
To help you decide whether information can be considered common knowledge, ask yourself:
- Who is my audience?
- What can I assume they already know?
- Will I be asked where I obtained my information?
- Did I have to look up the information?
- Will my audience know that I have the expertise relating to this information?