Plagiarism tutorial: Common knowledge

Common knowledge is a sometimes difficult concept that can be interpreted in different ways. Your history teacher may tell you that a piece of information that can be found in four or more sources is common knowledge and needs no citation, while your science teacher may want nearly everything cited, including facts that are known by many people. The facts below are likely to be considered common knowledge by your teacher:

• Abraham Lincoln was the 16th U.S. president.
   
• Much of the land in California was once owned by Mexico.
   
• Carbon is the sixth element on the Periodic Table.
   
• Mark Twain is the pen name used by the author Samuel Clemens.

In order to avoid any mistakes or confusion, be sure to ask your teacher about the definition of common knowledge for that class.

Some teachers will expand the idea of common knowledge to include information or ideas that are discussed in class. This can make the attribution/citation process even more confusing as there will be a good bit of variation from teacher to teacher. Use the following guidelines to avoid possible plagiarism:

• If you refer to something a classmate said about your topic during or outside of class, refer to that person within the written text or spoken presentation, and then write a properly formatted citation using the "Interview" example.
   
• If you refer to something your teacher said during a classroom lecture or presentation, refer to your teacher by name within the written text or spoken presentation, and then write a properly formatted citation using the "Speech or Lecture" example.
   
• If you mention a discussion from class that involved several people, or you don't remember who the person was who made a particular comment, refer to the discussion in your text or presentation and cite "Classroom Discussion" following the "Speech or Lecture" example.
   
• If your teacher allows ideas and topics discussed in class to be considered common knowledge ("in-class  knowledge"), you do not need to provide a citation but you should still refer to the classroom discussion within your text or presentation so everyone understands where the information came from.

Once again, be sure to ask your teacher for clarification so you don't make any mistakes.

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