In the sciences, a primary source is defined as a work that provides a full account of the research performed by the authors. A secondary source is a review or other commentary piece wherein the authors reflect on primary sources and the science completed by the authors of those primary sources. A tertiary resource is an encyclopedia or a textbook and is considered the furthest away from the primary sources if we were to put them on a timeline.
Primary: A researcher publishes a journal article on their most recent research on abiotic stresses in Arabidopsis.
Secondary: Another researcher publishes a review including the article written on abiotic stresses in Arabidopsis.
Tertiary: The research findings from the primary article are included in the textbook Plant Biology.
Government resources and other grey literature can be defined as information that may not be formally peer-reviewed and published in a traditional journal database. It is also very important in the sciences, as there are some sources that provide highly valuable information that will not be found elsewhere, like government reports. Grey literature can include sources like:
| Popular | Scholarly | |
| Authority | Written by a journalist, blogger, or staff writer. | Written by an expert in the field, like a scientist, doctor, or professor. |
| Scope | Broad in scope. Appealing to a wide range of readers. | In-depth. Usually written for a narrow audience. |
| Intended Audience | General public | Experts in the field or students in training. Academic peers of the author with similar credentials, background, and training. |
| Language | Accessible to the average person, fairly easy to read, usually about 8th-grade reading level. | Likely to contain highly field-specific language and jargon. (Review articles will be more accessible than original research papers.) |
| References to Other Resources | Includes few if any citations. May include links to other web pages in lieu of formal citations. | Includes many citations to other resources of a scholarly nature. |
| Purpose | Entertain or provide access to news stories. | Inform of recent scholarly research. |
| Layout | Varies widely depending on the resource. | Usually includes an introduction, methods, results, and discussion sections. Contains figures and tables. |
| Peer-review Status | Does not undergo a peer review process. If any review process is performed, it is by an editor. | Scholarly articles typically undergo a rigorous peer-review process after they have been submitted to a journal. The journal will accept or reject the article for publication based on the reviews from peers. |
| Examples |
News sites: bbc.com; Time Magazine Podcasts: Science Friday Popular Books: I Contain Multitudes: The Microbes Within Us and a Grander View of Life Websites: Hemoglobin page on Wikipedia; Seizures page on Mayo Clinic |
Journals: Molecular Biology Reports; Annual Review of Food Science and Technology Books published by academic publishers (Taylor & Francis, CRC Press, Oxford University Press): Fungi: Experimental Method in Biology; What is Life? How Chemistry Becomes Biology |
Resources Referenced in this tutorial:
Resource 1: Heavy metal contamination of prenatal vitamins
Resource 2: Prenatal vitamins: Why they matter, how to choose
Resource 3: Non-prescription Prenatal Multivitamin/mineral (MVM) Dietary Supplement National Study
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