A primary source is firsthand testimony or direct evidence concerning a topic, an event, a person's life, original works of literature, and historical facts. It consists of original materials that have not been filtered through interpretation, condensation, evaluation or any type of commentary. Primary sources are usually the first formal appearance of results and offer an immediate picture of the topic under investigation.
A secondary source is information about primary, or original information, which usually has been modified, selected, or rearranged after the fact, for a specific purpose or audience. It can be a description, an interpretation, an analysis, a commentary and an evaluation of an historical event or phenomenon, or the original writing of an author.
NOTE: Primary sources tend to stand on their own, while secondary sources are based on other sources, but it is not always easy to discern the difference between the two. The same document, or other piece of evidence, may be a primary source to one researcher and a secondary source to another.
FOR EXAMPLE: If you are doing research on Pearl Harbor, a newspaper article commemorating December 7th, 1941 is a secondary source. An article dated of December 7th, 1941 and reporting the attack on Pearl Harbor is a primary source.
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