Although crediting other authors for their work is important, you don’t need to document every fact and idea used in your document because some of that information falls under the category of common knowledge. Common knowledge is information that is widely known, such as the fact that the Declaration of Independence was signed in 1776. Or it might be the kind of knowledge that people working in a particular field, such as petroleum engineering, use on a regular basis.

If you’re relatively new to your topic, it can be difficult to determine whether information in a source is common knowledge. As you explore your topic, however, you will begin to identify what is generally known. For instance, if three or more sources use the same information without citing its source, you can assume that the information is common knowledge. However, if those sources cite the source of that information, make sure you cite it as well.