In the Sciences, primary sources are documents that provide full description of the original research. For example, a primary source would be a journal article where scientists describe their research on the human immune system. A secondary source would be an article commenting or analyzing the scientists' research on the human immune system
| Primary Source | Secondary Source | |
| DEFINITIONS | Original materials that have not been filtered through interpretation or evaluation by a second party. | Sources that contain commentary on or a discussion about a primary source. |
| TIMING OF PUBLICATION CYCLE | Primary sources tend to come first in the publication cycle. | Secondary sources tend to come second in the publication cycle. |
| FORMATS--depends on the kind of analysis being conducted. | Conference papers, dissertations, interviews, laboratory notebooks, patents, a study reported in a journal article, a survey reported in a journal article, and technical reports. | Review articles, magazine articles, and books |
| Example: Scientists studying Genetically Modified Foods. | Article in scholarly journal reporting research and methodology. | Articles analyzing and commenting on the results of original research; books doing the same |
Examples of Primary and Secondary Sources
| Primary Source | Secondary Source |
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Source: The Evolution of Scientific Information (from Encyclopedia of Library and Information Science, vol. 26).