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HORT 4099 Horticulture Capstone: Primary and Secondary Sources

Course guide for Hort 4099 and a great starting place for research.

What is the difference between Primary and Secondary?


Primary sources are original materials (research, objects, documents) from the time period under study. They have not been interpreted, summarized, or analyzed. They were created during the period being studied and documents in some way what is being studied.

  • Raw material or first-hand information
  • Eyewitness, historical, or legal documents
  • Artifacts (coins, clothing, furniture from the time under study)
  • Letters, diaries, photographs
  • Works of art, architecture, literature, music 

These examples from the Lousiana Digital Library are all primary sources:

Draft board summons

Draft board summons

Flying Mallard decoy

Flying Mallard decoy
Snapshot of Zutty Singleton at Vasquez Rocks

Snapshot of Zutty Singleton at Vasquez Rocks

Iberville Gazette frontpage

Iberville Gazette frontpage

Souvenir ribbon

Souvenir ribbon

Mistick Krewe de Comus costume

In the sciences, primary sources means original research data, original research articles, or new scientific ideas or discoveries written/prepared by the scientists who performed the experiments or came up with that discovery.

  • Conference proceedings
  • Dissertation or thesis
  • Patent
  • Technical report
  • Lab notebook

Primary source articles are factual, not interpretive. They are written by the scientists who performed the research. 

Importantly, articles that are primary sources in the sciences generally follow IMRD format--Introduction, Methods, Results, and Discussion. Sometimes you can even tell from the abstract if it is a primary source based on if it follows IMRD format.

Looking at the structure of the article can help you understand if it is an original research article:

As you see, primary sources in the sciences still include citations even though they are original research. That is because this research is grounded in other research. 

A secondary source is one step removed from the event and analyzes or interprets the primary sources. It can be published or unpublished works. 

  • Reviews
  • Critical analysis
  • Second-person account
  • Biographical or historical studies

​Here are some examples from LSU Libraries' collections:

A book reviewA book review

A biographical book

In the sciences, secondary sources are known as review articles. These can be tricky to identify. They also include citations and may look like original research but they are a discussion and evaluation of someone else's research, not a presentation of original research. 

In this example, some terms in the abstract indicate that it is a review article. These terms show how the authors were using the research of others to evaluate services:

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