Researching: Primary, Secondary, and Tertiary Sources
When doing research in a library, it's often best to consider the sources you find on the shelves. Librarians choose books for a variety of reasons, but the reference collection contains the most accurate and up-to-date sources the library can find. The three types of resources found in libraries are primary, secondary, and tertiary sources.
A primary source is the document or item that shows original thinking, discovery, or new information. Often in research these are the most important items to use because they have not been filtered through anyone's opinion but the creators. Examples of primary sources include diaries, works of art, literature, emails, photographs, constitutions, legal statutes, and many other creations. Most public libraries do not have many nonfiction primary sources, but some may contain maps, yearbooks, local history and genealogy collections.
A secondary source is a commentary on a primary source. This means that instead of creating something new, the author is giving his opinion or restating something that has already been expressed. These types of sources are often used in research to back up an opinion or point of view the researcher wishes to present. Secondary sources can be journal articles, biographies, summaries, criticisms, and many others. This type of resource is most used in the library, especially in journal databases and newspapers.
Tertiary Sources are documents made up of many primary or secondary sources on a single topic or a variety of topics. Often college level classes will not allow the use of tertiary sources because they can be seen as redundant for restating secondary sources or having a biased opinion, but some professors and most high school classes allow them. Examples include dictionaries and encyclopedias as well as other fact books and manuals that are often found in reference collections.
If you keep in mind the types of sources you can find in a library, you can better use them to help strengthen any research paper.