Common knowledge is knowledge that is publicly known by everyone or nearly everyone, usually with reference to the community in which the knowledge is referenced. Common knowledge can be about a broad range of subjects, such as science, literature, history, or entertainment. Since individuals often have different knowledge bases, common knowledge can vary and it may sometimes take large-scale studies to know for certain what is common knowledge amongst large groups of people. Often, common knowledge does not need to be cited. Common knowledge is distinct from general knowledge.