Comparing Secondary and Primary Sources

by Melissa Callahan, education outreach coordinator, Encyclopedia of Greater Philadelphia

For any historical research project, you need to use evidence in order to support your thesis. Evidence can be drawn from two different types of sources - secondary and primary. Before you begin your research, it is important that you understand the differences between these two types of sources. Check out the handy information below to get started.

Below the tables, we have answered some additional questions you might have.

Basic Questions

Secondary Source Primary Source
What is it? Any text or object that analyzes, interprets, comments upon, or evaluates primary source material. Your completed NHD project, for example, will be a secondary source! The author or creator of a secondary source was not there - in fact, s/he probably wasn't born yet! Any text or object that provides a firsthand account of the event, time period, or person in question. The author or creator of a primary source was actually there or knew someone who was.
Why should I use this type of source? to get a general overview of or basic facts about your topic; to help you place your topic within the larger historical context in which the event happened or the person lived; to learn about and evaluate interpretations that other researchers have developed on the topic you selected; to identify primary and additional secondary sources related to your topic (using the citations or bibliography). to understand what it was like to live through or take part in an historical event or time period; to connect more directly and personally with an event or person from the past; to examine multiple viewpoints about the event or time period from the people who were there; to help you understand not only what people in the past did, but also why they did it; to develop important critical thinking skills and draw your own conclusions about the past.

General Examples

General Examples
Secondary Sources Primary sources
Text: An article from a scholarly journal; a book (especially one written by a professional historian, social scientist, biographer, etc.); reference books such as a textbook or encyclopedia; a poem, novel or short story written about an event, a time period, or a person in the past.

Objects: A current work of art that depicts or interprets an event from the past.

Audio/Visual: A documentary film; a popular film, play, or piece of music written about an event, a time period, or person in the past.
Text: A speech; legal or government documents; an eyewitness statement or interview; newspaper or magazine article written at the time or shortly thereafter; a memoir or autobiography; diary or journal; correspondence (letter, email, text message, etc.); a poem, novel, or short story written by a participant or eyewitness.

Objects: an original work of art; clothing from the era; communication devices; household items.

Audio/Visual: Film, audio, or a photograph of an event taken as it happened or depicting the immediate aftermath; music from the era; an oral history or recorded interview.

Statistics/Data: A census; a survey; results of a scientific experiment; weather reports.

Detailed Comparisons

Secondary Sources Primary sources
"Crusade for freedom: William Still and the real Underground Railroad" by James Oliver Horton, in Passages to Freedom: The Underground Railroad in History and Memory, edited by David Blight (2004) Journal C of Station No. 2 of the Underground Railroad, Agent William Still, 1852-1857, available online from the Historical Society of Pennsylvania
"Lynching" by Dennis B. Downey. Article available online from the Encyclopedia of Greater Philadelphia. "How Enfranchisement Stops Lynching," Original Rights Magazine, vol. I, no. 4 (June 1910): 42-52. Available online from the University of Chicago Library.
A Brief History of Japanese American Relocation During World War II, available online from the National Parks Service Interview of Dillon S. Meyer on the Relocation of Japanese - Americans, audio file available online from the National Archives
Jewish-American Artists and the Holocaust by Matthew Baigell (1997) Night by Elie Weisel
"The Environmental Protection Agency (EPA)" article available online from the Encyclopedia Britannica Text of Reorganization Plans 3 and 4 of 1970, available online from the National Archives


Additional Questions:

How can I tell the difference between a primary and secondary source?

This can be tricky! However, the date the source was created is often a determining factor. For example, if the topic of your research is the liberation of Nazi concentration camps, then a newspaper article that reports the liberation of Dachau published in May 1945 would be a primary source while a newspaper article commemorating the 70th anniversary of the liberation of Dachau published in 2015 would be a secondary source. However, if you are researching the ways in which people commemorate events that are associated with tragedy, the 2015 article would be a primary source.

How can I determine whether or not I can trust the information I get from a secondary source? In other words, how do I know if the source is reliable?

A good secondary source usually includes citations and/or a bibliography. Check the author's references and make sure that most of his or her evidence comes from primary sources. In addition, research the author. Find out what qualifies this person to write about this particular topic. For example, a history professor at Rutgers University who specializes in the Early Republic probably would be qualified to write an article about Thomas Jefferson. If you have difficulty finding information about the author, or if the author's credentials do not seem to relate to the topic in any way, the source might not be reliable. Finally, the publisher can serve as a clue. Examples of sources that you can probably trust based on the publisher include an article published in a scholarly journal; a book published by a university; an article or blog posted on a university or government agency website.

How can I determine whether or not I can trust the information I get from a primary source? In other words, how do I know if the source is reliable?

It is important to remember that people everywhere and in every time period have their own thoughts, feelings, and perspectives about the world in which they live. All sources (both primary and secondary) reflect the opinion or bias of the creator. In some cases, the author or creator may provide false or misleading information (either intentionally or unintentionally). Just because it is old and written down does not mean that it is true!

Therefore, it is important to analyze multiple primary sources in order to get a more complete and accurate picture of what actually happened. It also is important to research the author or creator. Information about his or her background might give you some clues about their possible biases. Background information might also tell you whether this person would have a motive to provide false or misleading information.

Finally, the intended audience is important. Think about it this way - if you wrote a letter to your parents, a letter to your teacher, and a letter to your best friend describing what you did at camp this summer, would you include exactly the same information in all three letters? Probably not! In what ways might these three letters be different?

Where can I find secondary sources related to my topic?

Your history textbook is a great place to start! You also can visit your school or local library - be sure to speak with the librarian about your topic and your research goals. Finally, there are many reliable secondary sources on the Internet -but you must be careful! Since virtually anyone can post anything online, the Internet is also a haven of misleading and false information. Government websites (sites that end in .gov) and the websites of educational institutions (sites that end in .edu) can be trustworthy sources of both secondary and primary sources. You can also check the websites of historical societies for secondary source information. Here are some specific examples of trustworthy sites:

Where can I find primary sources related to my topic?

Many institutions including libraries, museums, historical societies, colleges and universities, and government agencies collect, preserve, and make primary sources available for research. Oftentimes, you can search the catalogues of these institutions online. Through the Philadelphia Area Consortium of Special Collections Libraries (PACSCL) website, for example, you can search several institutions at once. Some institutions have digitized a portion of their holdings and made them available online. Many presidential libraries such as the John F. Kennedy Library and Museum in Massachusetts offer digital collections. Other examples include:


Melissa Callahan is an experienced social studies teacher who is the education outreach coordinator for The Encyclopedia of Greater Philadelphia and a graduate student in history at Rutgers-Camden