These sources provide an analysis or reformulation of primary sources. They often try to describe or explain primary sources. These are usually works that summarize, interpret, reorganize or add value to a primary source. They are sources that index, summarize, organize, compile or digest other sources. Some reference materials and manuals are considered tertiary sources if their primary purpose is to list, summarize, or simply repackage ideas or other information. Tertiary sources are generally not attributed to a specific author. These sources are recordings of events or evidence as first described or that actually took place without interpretation or commentary. This is information that is shown for the first time or original materials on which further research is based. Primary sources show original thinking, report new discoveries or share new information. Examples of primary sources include theses, dissertations, scientific journal articles (research-based), selected government reports, symposia and conference proceedings, original artwork, poems, photographs, speeches, letters, memos, personal accounts, diaries, interviews, autobiographies, and correspondence. Sources of information or evidence are often classified as primary, secondary or tertiary material. These classifications are based on the originality of the material and the proximity of the source or origin. This tells the reader whether the author is reporting first-hand information or conveying the experiences and opinions of others considered second-hand.
It can be difficult to determine whether a source is primary, secondary or tertiary. Below is a description of the three categories of information and examples to help you decide. Examples of tertiary sources include dictionaries/encyclopedias (may also be secondary), almanacs, information books, Wikipedia, bibliographies (may also be secondary), directories, travel guides, textbooks, textbooks and manuals (may be secondary), indexing and abstraction of sources. Examples of secondary sources include textbooks, edited works, books and articles that interpret or review research papers, histories, biographies, literary criticism and interpretations, law and legislative reviews, political analysis and commentary.
