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GEOG 1218 - Our Dynamic Earth: Types of Sources

Types of Sources

Types of Sources

Information is found everywhere, but not all information sources are the same. To start thinking about the types of sources we use when we look for information, let's consider the process it took to create that information:

  1. As original research is completed, those initial findings generally produce a primary source.
  2. Those research findings are then evaluated and interpreted further by experts in the field to create a secondary source.
  3. Once the findings have been discussed and generally agreed upon, tertiary sources are created to summarize the information.

Use the tabs below to explore primary, secondary, and tertiary sources.

Primary, Secondary, and Tertiary Sources

Primary Sources

Primary sources are products of original research. Primary sources are the first appearance of research findings (publications and presentations) and often provide a description of how the original research was conducted. In the sciences, these often include data sets and results found from empirical observations and experiments. Primary sources form the basis for further research and interpretations on a subject as new ideas may not be fully refined or validated within the original study (ex. a secondary source uses a primary source to validate and interpret results). 

Examples include:

  • Artifacts (specimens and samples)
  • Conference proceedings
  • Data sets and statistics
  • Interview transcripts, audio recordings, or video recordings
  • Journal articles describing original research on a topic
  • Lab notebooks
  • Letters
  • Original experiment results
  • Original documents
  • Patents
  • Photographs
  • Technical reports
  • Theses and dissertations

Secondary Sources

Secondary sources are accounts written after an event or original research has taken place to interpret, discuss, and evaluate a primary source. They tend to summarize existing knowledge so can be used to compare different ideas and theories over time. Since a secondary sources include commentary, the context of the writing is important to consider when evaluating the value of the source to your research.

Examples include:

  • Biographies
  • Books
  • Commentaries and criticisms
  • Journal articles
  • Magazine articles
  • Newspaper articles
  • Reviews
  • Websites

Tertiary Sources

Tertiary sources are a generalized resource that use distilled and condensed information. While they rarely contain original material, they tend to include a collection of references tracing back to primary and secondary sources. Tertiary sources can be a good starting place for your research to look up data or get an overview of your topic.

Examples include:

  • Almanacs
  • Dictionaries
  • Directories and Indexes
  • Encyclopedias
  • Handbooks, Factbooks, and Guidebooks
  • Textbooks
Subject Primary Source Secondary Source Tertiary Source
Biology Case study of Zika patient Review article about Zika Encyclopedia entry on Zika
Chemistry Chemical patent Book about chemical reactions Table of related reactions
Agriculture Results from a scientific GMO study Journal article about GMOs Encyclopedia entry on GMOs

Source: Virginia Tech University Libraries. Primary, secondary, and tertiary sources.

Popular and Scholarly Sources

Popular and Scholarly Sources

In addition to identifying sources as primary, secondary, or tertiary, sources can also be classified as popular or scholarly. Scholarly sources tend to be peer-reviewed (a rigorous editing process in which experts verify the information). To start thinking about the types of sources we use when we look for information, let's think about the author, the intended audience, and the publishing process.

Use the tabs below to explore the differences between popular and scholarly sources.

Popular vs. Scholarly Sources

Popular vs. Scholarly Sources


Popular Sources

Imagine the types of magazines and newspapers that you would find at a bookstore or in the grocery store. We refer to these types of periodicals as "popular sources"; they are geared to reach a more general audience and written in non-technical language. 


Examples include magazines, newspapers, websites, blogs, etc. Search and browse the following popular science resources to locate an article.

Scholarly Sources

In contrast to popular sources, scholarly sources are written primarily by scientists, for scientists. The goal of a scholarly source is to communicate new scientific research in the context of past research. The language in scholarly sources is often technical and publishing often follows a rigorous editing and approval process making the final product peer-reviewed.


Examples could include articles, reviews, conference papers, grey literature, books, etc. Scholarly journal titles include: Nature, Proceedings of the National Academy of Science, ACS journals. Visit some of the geography databases below to search and browse for scholarly articles.  


Verify Peer-Reviewed Sources

Look up a journal title (not an individual article title) in Ulrichsweb with the link below to verify whether the journal is peer-reviewed.


Look for this referee jersey icon in the Ulrich search results to confirm that a journal is refereed/peer-reviewed. Refereed journals use a review process in which articles are reviewed by experts and respected researches to verify the validity and value of the article to the field.