• Primary sources or firsthand accounts (information in its original form, not translated or published in another form),
• Secondary sources or secondhand information (a restatement, analysis, or interpretation of original information),
• Tertiary sources or third-hand information (a summary or repackaging of original information, often based on secondary information that has been published).

Here are examples to illustrate the first-handedness, second-handedness, and third-handedness of information:

Primary Sources–Because it is in its original form, the information in primary sources has reached us from its creators without going through any filter. We get it firsthand. Here are some examples that are often used as primary sources:

• Any literary work, including novels, plays, and poems,
• Breaking news,
• Diaries,
• Advertisements,
• Music and dance performances,
• Eyewitness accounts, including photographs and recorded interviews,
• Artworks,
• Data,
• Blog entries that are autobiographical,
• Scholarly blogs that provide data or are highly theoretical, even though they contain no autobiography,
• Artifacts such as tools, clothing, or other objects,
• Original documents such as tax returns, marriage licenses, and transcripts of trials,
• Websites, although many are secondary,
• Buildings,
• Correspondence, including email,
• Records of organizations and government agencies,
• Journal articles that report research for the first time (at least the parts about the new research, plus their data).

Secondary Source–These sources translate, repackage, restate, analyze, or interpret original, primary source information. Thus, the information comes to us secondhand, or through at least one filter. Here are some examples that are often used as secondary sources:

• All nonfiction books and magazine articles except autobiography,
• An article or website that critiques a novel, play, painting, or piece of music,
• An article or web site that synthesizes expert opinion and several eyewitness accounts for a new understanding of an event,
• The literature review portion of a journal article.

Tertiary Source – These sources further repackage the original information because they index, condense, or summarize the original.

Typically, by the time tertiary sources are developed, there have been many secondary sources prepared on their subjects, and you can think of tertiary sources as information that comes to us “third-hand.” Tertiary sources are usually publications that you are not intended to read from cover to cover but to dip in and out of for the information you need. You can think of them as a good place for background information to start your research but a bad place to end up. Here are some examples that are often used as tertiary sources:

• Almanacs,
• Dictionaries,
• Guide books, including the one you are now reading,
• Survey articles,
• Timelines,
• Bibliographies,
• Encyclopedias, including Wikipedia,
• Most textbooks.

Tertiary sources are usually not acceptable as cited sources in high school and university research projects because they are so far from firsthand information. That’s why most teachers don’t want you to use Wikipedia as a citable source: the information in Wikipedia is far from original information. Other people have considered it, decided what they think about it, rearranged it, and summarized it–all of which is actually what your teachers want you, not another author, to do with information in your research projects.

ACTIVITY: Which Kind of Source? Open activity in a web browser.

Adapted and copied from:

Chapter 2: "Types of Sources," in Choosing & Using Sources: A Guide to Academic Research by Teaching & Learning, Ohio State University Libraries is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.