Primary and secondary sources
Primary sources (e.g. statistical data, autobiographies or interview transcripts) contain raw information that has not been analyzed, summarized or interpreted, while secondary sources (e.g. literature reviews, documentaries, or books) are interpreted, evaluated or synthesized.
In general, primary sources are considered more credible than secondary sources because raw information is never wrong. An interpretation or analysis, on the other hand, can be wrong.
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|
Example: researching the moon landing
A filmmaker is making a documentary about the moon landing. Both primary and secondary sources are consulted to make the documentary as close to the truth as possible.
In this situation, primary sources include photographs, videos and interview transcripts with the astronauts. Secondary sources include newspaper articles covering the moon landing, other documentaries and books.
The documentary itself is also a secondary source because the information is analysed and interpreted.
Example: researching study habits of students
A student is researching the study habits of college students. He conducts a survey to collect primary information. The raw, statistical data from this survey is a primary source. The student also analyses scholarly journal articles on the topic. These are considered secondary sources, just as the paper of the student.
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 page
- 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.