Definition & Characteristics of Sources
Definitions of what is primary or secondary differs across the disciplines. For the sciences, this is how we would define the different types of sources:
Primary source literature in the sciences:
- documents the results of original research
- is written by those who have conducted the research
- includes firsthand information about their methodologies, data, results, or conclusions.
Secondary source literature in the sciences:
- summarizes, compares, critiques, or interprets the primary literature.
Tertiary sources in the sciences:
- are collections of primary and/or secondary sources.
Characteristics of primary sources in the sciences include:
- Report original research, ideas, or scientific discoveries for the first time
- Report results/findings/data from experiments or research studies
- May also be referred to as primary research, primary articles, or research studies
- DO NOT include meta-analyses, systematic reviews, or literature reviews - these are secondary sources
- Are frequently found in peer-reviewed or scholarly journals
- Should explain the research methodology used (randomized controlled trial, etc)
- Frequently include methods, results, and discussion sections
- Are factual, not interpretive
Examples of Sources
| Primary Sources | Secondary Sources |
| Research articles published in scholarly, peer-reviewed journals | Summaries, critiques, or interpretations of primary literature |
| Clinical trials | Review articles |
| Interviews | Textbooks (can also be a tertiary source) |
| Correspondence | Dictionaries (can also be a tertiary source) |
| Patents | Directories (can also be a tertiary source) |
| Lab notebooks | Encyclopedias (can also be a tertiary source) |
| Data sets | |
| Theses & dissertations | |
| Technical Reports |
Where to find primary sources
To find primary source literature in the sciences, use library databases. Research guides can help you identify databases for the discipline you are interested in.
Note: The library databases may contain references to both primary and secondary literature. You will need to examine each resource carefully to determine which one it is.
Reading Primary Literature in Biology
