Primary and secondary sources
Primary sources (e.g. interviews, surveys and statistical data) are first-hand and considered authoritative, while secondary sources (e.g. literature reviews, documentaries, books) analyze, interpret, evaluate and synthesize primary information.
Secondary sources or further removed from the event being described and are therefore considered less credible and reliable.
Table of contents
What is a primary source?
Primary sources are the original evidence of certain events, objects, persons or work. They enable students and researchers to get as close as possible to the actual event. The information in primary sources has not yet been analyzed, summarized or interpreted, which gives you the opportunity to do so yourself.
Examples of primary sources are:
- Experiment results
- Statistical data
- Eyewitness accounts
- Surveys and interviews
- Legal documents
Primary source example 1:
Imagine a historical event that you are researching – say the moon landing. Of course, you can’t go back in time and experience the event yourself, so you decide to start looking for eyewitness reports, photographs, and videos taken that day. These are examples of primary sources, because they are the closest, most original accounts of the actual historic event.
Primary source example 2:
A professor is researching the study habits of college students. He uses a survey to gather data and conducts interviews with college students. The professor reports his findings and publishes them in a journal. This research is considered a primary source because it includes the original raw data, without any outside interpretation.
What is a secondary source?
A secondary source interprets, analyzes and/or explains primary sources. These sources are one or more steps removed from the original event and therefore sometimes lack the immediacy of the original content.
Some examples of secondary sources include:
- Literature reviews
- Opinion pieces
- Television broadcasts
Secondary source example 1:
A filmmaker decides to make a documentary about the moon landing. He analyzes, interprets and explains the original primary source evidence, such as the photographs and eyewitness reports we mentioned earlier. This documentary is considered a secondary source, because it’s one step removed from the primary source.
Secondary source example 2:
A student decides to write a paper on the study habits of students, just like the professor did in the earlier example. While doing research, the student finds the article published by the professor and decides to use it in his literature review, along with some other articles. The student interprets and compares the professor’s article to other publications. The student’s paper is considered a secondary source because it’s based upon and interprets the primary source (i.e. the article published by the professor).
Video explaining primary and secondary sources
Primary and secondary source examples
|Academic discipline||Primary source||Secondary source|
|Art||Painting by Van Gogh||Exhibition catalog explaining and interpreting the painting|
|Science||Empirical study||Literature review describing the study|
|Journalism||Newspaper from World War II||Thesis exploring the media coverage of World War II|
|History||Ancient object from the Middle Ages||Museum catalog describing the ancient object|
|Economy||Autobiography by Warren Buffett||Third-party book about Warren Buffet|
|Biology||Original research about how the brain functions||Blog post about the findings of this research|
|Mathematics||Research on new mathematical models to calculate a rocket launch||Book explaining and teaching these mathematical models|
|Engineering||Patent||Article about this patent and its applications|
|Law||Declaration of Independence||Documentary about the creation of the Declaration of Independence|
Questions to ask yourself
To help you determine whether a source is primary or secondary, there are some simple questions you can ask yourself:
- Was the source created at the time and/or location of the event or time period? (e.g. a photograph of the moon landing)
- Was the person who created the source directly involved in the event or time period
- Does the source provide an outlet for persons who were directly involved in the event or time period to share their story?
- Is the source a piece of art, a work of literature, a film created by or starring your subject of study, or a photograph?
- Is the source a legal document, an original collection of data or statistics, or a personal communication?
If the answer to any of these questions is yes, then it’s most likely a primary source.
Context can influence which sources are primary sources
It’s important to be aware that your research focus and your research question have an impact on what is considered to be a primary source for your specific research.
Let’s say you write a paper about the September 11 attacks. You could consult primary sources such as news articles written at the time, photographs, TV news clips, interviews with people who were onsite, and radio clips from that time. Secondary sources could include documentaries or newspaper articles.
Now let’s assume your paper is not about the September 11 attacks itself, but about the media coverage of the September 11 attacks. In this scenario, the documentaries and newspaper articles become the primary sources.
Primary vs. secondary sources: which is better?
In general, primary sources are considered more credible and authoritative. They report actual evidence, and evidence cannot be wrong.
However, there are secondary sources (e.g. literature reviews) that combine a great deal of prior research and analyze the collection of research from a unique perspective. Using and citing such a literature review could add great value to your own research.
Your research will involve the use of both primary and secondary sources. Even if you are conducting a scientific experiment, you will draw upon previous methods used by others, existing theories, and complete a review of the extant literature.
Locating primary sources
If you are not conducting an experiment or gathering the primary data yourself, the best way to find primary sources is through secondary sources.
Most often, finding the primary source upon which a secondary source is based is fairly easy, as the information should be readily shared.
You’ll find this information in three key places in the secondary source:
- Reference list
- Internet links, in the case of online resources
For example, let’s say you find an interesting quote from Barack Obama cited in a news article: “As Obama said in a 1995 interview with the Washington Post…” It’s clear that you need to locate the original Washington Post interview, as the interview is the primary source.
For this reason, it is crucial that you complete a thorough literature review, paying attention to the primary sources upon which your secondary sources are based.