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How to Write an Annotated Bibliography: Primary and Secondary Sources

Primary versus Secondary Sources

Primary vs. Secondary Videos


Primary, Secondary, & Tertiary Sources
The content of research papers may come from different types of sources, such as:

  • Your own opinion and analysis
  • Primary sources
  • Secondary sources
  • Tertiary sources

It may not be necessary to include each of these types of sources in every paper you write, but your instructor may require you to include them. It is important to understand the characteristics of primary, secondary and tertiary sources–they each serve a different purpose throughout the research process, and can strengthen your assignment, too.

It can be difficult to figure out if a source is considered primary, secondary, or tertiary. We will explain the differences and provide examples of each in this tutorial. If you are still not sure if a source you would like to use is primary, secondary, or tertiary, ask a librarian or teacher.

What is a Primary Source?
Primary sources are first-hand, authoritative accounts of an event, topic, or historical time period. They are typically produced at the time of the event by a person who experienced it, but can also be made later on in the form of personal memoirs or oral histories.

Anything that contains original information on a topic is considered a primary source. Usually, primary sources are the object discussed in your paper. For instance, if you are writing an analysis on Upton Sinclair’s The Jungle, the book would be a primary source. But, just because a source is old does not mean it is a primary source.

Some examples of original, first-hand, authoritative accounts include:

  • Letters, diaries or journals (Personal thoughts)
  • Original photographs
  • First-hand newspaper reports
  • Speeches, autobiographies
  • Memoirs
  • Creative works like plays, paintings and songs
  • Research data and surveys

What is a Secondary Source?
Secondary sources interpret or critique primary sources. They often include an analysis of the event that was discussed or featured in the primary source. They are second-hand accounts that interpret or draw conclusions from one or more primary sources.

Some examples of works that interpret or critique primary sources include:

  • Textbooks (May also be considered tertiary)
  • Essays or reviews
  • Articles that analyze or discuss ideas and events
  • Criticisms or commentaries

What is a Tertiary Source?
Tertiary sources generally provide an overview or summary of a topic, and may contain both primary and secondary sources. The information is displayed as entirely factual, and does not include analysis or critique. Tertiary sources can also be collections of primary and secondary sources, such as databases, bibliographies and directories.

Some examples of sources that provide a summary or collection of a topic include:

  • Textbooks (May also be considered secondary)
  • Almanacs
  • Bibliographies or abstracts
  • Wikipedia articles
  • Encyclopedias

Using Primary, secondary and Tertiary Sources in Research
Let’s say you are writing a research paper on the Equal Rights Amendment (ERA) of 1972, but you are unfamiliar with it. A good place to gather a general idea or understanding of the ERA would be a tertiary source, such as Wikipedia or the Encyclopedia Britannica. There, you can read a summary of events on its history, key people involved, and legislation.

To find more in-depth analysis on the Equal Rights Amendment, you consult a secondary source: the nonfiction book Why We Lost the ERA by Jane Mansbridge and a newspaper article from the 1970’s that discuss and review the legislation. These provide a more focused analysis of the Equal Rights Amendment that you can include as sources in your paper (make sure you cite them!). A primary source that could bolster your research would be a government document detailing the ERA legislation that initially passed in Congress, giving a first-hand account of the legislation that went through the House and Senate in 1972.

This video provides a great overview of primary and secondary sources: