Primary Research Sources vs. Secondary Research Sources
Most scholarly articles and books in the library system can be categorized as either primary research or secondary research. Primary sources provide the most direct data about a phenomenon, and they include eye-witness accounts or data that researchers observed with their own eyes or scientific instruments. In contrast, secondary research is more indirect because it provides a reflection and an interpretation of what the primary sources reported.
Sciences & Social Sciences
Primary Research Studies: In the hard sciences and social sciences, primary research sources are articles and books that report directly on research studies that the authors conducted themselves. The data is derived from directly observing and analyzing some phenomenon. Examples would include peer-reviewed articles reporting on exploratory, descriptive, or experimental research. You can usually determine if an article is a primary research study by reading the abstract and the headings. If the article has a "Methods" section that explains how the data was collected and/or analyzed, the article is probably an example of primary research.
Secondary Research Studies: In the hard sciences and/or social sciences, secondary research sources are articles and books that analyze and synthesize the findings of primary research studies to answer some kind of research question. The purpose is not to report directly on a single study that the authors did themselves. Instead, the purpose is to compare the findings of a wide group of researchers in order to see if a trend emerges. If you see any of the following keywords in the title or abstract of an article, it is probably a secondary research study: "review article," "review," "systematic review," "meta-analysis." Books/e-books that explain a topic by referring to past research are usually considered secondary sources as well.
Arts & Humanities
In humanities fields such as history, primary and secondary sources are defined a little bit differently compared to scientific fields. Read more about this distinction on our library guide to primary historical sources: Primary Sources: Across Disciplines.