When you do research, you have to gather information and evidence from a variety of sources.

Primary sources provide raw information and first-hand evidence. Examples include interview transcripts, statistical data, and works of art. Primary research gives you direct access to the subject of your research.

Secondary sources provide second-hand information and commentary from other researchers. Examples include journal articles, reviews, and academic books. Thus, secondary research describes, interprets, or synthesizes primary sources.

Primary sources are more credible as evidence, but good research uses both primary and secondary sources.

What is a primary source?

A primary source is anything that gives you direct evidence about the people, events, or phenomena that you are researching. Primary sources will usually be the main objects of your analysis.

If you are researching the past, you cannot directly access it yourself, so you need primary sources that were produced at the time by participants or witnesses (e.g. letters, photographs, newspapers).

If you are researching something current, your primary sources can either be qualitative or quantitative data that you collect yourself (e.g. through interviews, surveys, experiments) or sources produced by people directly involved in the topic (e.g. official documents or media texts).

What is a secondary source?

A secondary source is anything that describes, interprets, evaluates, or analyzes information from primary sources. Common examples include:

• Books, articles and documentaries that synthesize information on a topic
• Synopses and descriptions of artistic works
• Encyclopedias and textbooks that summarize information and ideas
• Reviews and essays that evaluate or interpret something

When you cite a secondary source, it’s usually not to analyze it directly. Instead, you’ll probably test its arguments against new evidence or use its ideas to help formulate your own.

Primary and secondary source examples

Examples of sources that can be primary or secondary

A secondary source can become a primary source depending on your research question. If the person, context, or technique that produced the source is the main focus of your research, it becomes a primary source.

Documentaries

If you are researching the causes of World War II, a recent documentary about the war is a secondary source. But if you are researching the filmmaking techniques used in historical documentaries, the documentary is a primary source.

Reviews and essays

If your paper is about the novels of Toni Morrison, a magazine review of one of her novels is a secondary source. But if your paper is about the critical reception of Toni Morrison’s work, the review is a primary source.

Newspaper articles

If your aim is to analyze the government’s economic policy, a newspaper article about a new policy is a secondary source. But if your aim is to analyze media coverage of economic issues, the newspaper article is a primary source.

How to tell if a source is primary or secondary

To determine if something can be used as a primary or secondary source in your research, there are some simple questions you can ask yourself:

• Does this source come from someone directly involved in the events I’m studying (primary) or from another researcher (secondary)?
• Am I interested in evaluating the source itself (primary) or only using it for background information (secondary)?
• Does the source provide original information (primary) or does it comment upon information from other sources (secondary)?

Primary vs secondary sources: which is better?

Most research uses both primary and secondary sources. They complement each other to help you build a convincing argument. Primary sources are more credible as evidence, but secondary sources show how your work relates to existing research. Tertiary sources are often used in the first, exploratory stage of research.

What do you use primary sources for?

Primary sources are the foundation of original research. They allow you to:

• Make new discoveries
• Provide credible evidence for your arguments
• Give authoritative information about your topic

If you don’t use any primary sources, your research may be considered unoriginal or unreliable.

What do you use secondary sources for?

Secondary sources are good for gaining a full overview of your topic and understanding how other researchers have approached it. They often synthesize a large number of primary sources that would be difficult and time-consuming to gather by yourself. They allow you to:

• Gain background information on the topic
• Support or contrast your arguments with other researchers’ ideas
• Gather information from primary sources that you can’t access directly (e.g. private letters or physical documents located elsewhere)

When you conduct a literature review or meta analysis, you can consult secondary sources to gain a thorough overview of your topic. If you want to mention a paper or study that you find cited in a secondary source, seek out the original source and cite it directly.

Remember that all primary and secondary sources must be cited to avoid plagiarism.