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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 think about the process of creating that information:
As original research is completed, those initial findings generally produce a primary source.
Those research findings are then evaluated and interpreted further by experts in the field to create a secondary source.
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 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).
Artifacts (specimens and samples)
Data sets and statistics
Interview transcripts, audio recordings, or video recordings
Journal articles describing original research on a topic
Original experiment results
Theses and dissertations
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.
Commentaries and criticisms
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.
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.
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.
Discover delivers: the latest news, theories, and developments in the world of science; compelling stories and breakthroughs in health, medicine, and the mind; environmental issues and their relevance to daily life; cutting-edge technology and its impact on our future; and thought-provoking articles from award-winning editors, opinion makers, Nobel laureates, and renegade scientists.
The New York Times is an American daily newspaper, founded and continuously published in New York City since September 18, 1851, by The New York Times Company. The New York Times has won 117 Pulitzer Prizes, more than any other news organization.
The Scientist is the magazine for life science professionals—a publication dedicated to covering a wide range of topics central to the study of cell and molecular biology, genetics, and other life-science fields.
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 biology databases below to search and browse for scholarly articles.
A rapid way to search 25+ biology-related databases all at once, including MEDLINE, TOXNET, ASFA, and more. Source types include scholarly journals, trade journals, conference proceedings, books, government publications, magazines, newspapers, reports, video and audio. Date range varies based on what databases ProQuest chooses to include in the collection.
Publishes journals and online databases across the life, physical and applied sciences and, most recently, clinical medicine. Content encompasses daily news from award-winning journalists, expert opinion and practical methodology, and more high impact research and reviews than any science publisher.
PNAS is one of the world's most-cited and comprehensive multidisciplinary scientific journals, publishing more than 3,100 research papers annually. Every published paper is peer reviewed and has been approved for publication by an NAS member.
Provides multidisciplinary coverage of high-impact scholarly literature in the sciences, social sciences, arts, and humanities. Use the unique Cited References Search to find articles that cite an author or work -- this allows you to track citations forward in time. Content dates from 1900 - present. Includes Science Citation Index Expanded, Social Sciences Citation Index, Arts & Humanities Citation Index, and Emerging Sources Citation Index.
Access Ulrichsweb with the link below to verify information about a journal or publication:
UlrichswebThis link opens in a new windowUlrich's (Ulrichs) contains bibliographic data about all periodicals published worldwide, and includes reviews from Magazines for Libraries and Library Journal.
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.