Primary Data: Data that has been generated by the researcher himself/herself, surveys, interviews, experiments, specially designed for understanding and solving the research problem at hand. Examples are Technical Reports, Conference Proceedings, Journal articles.
Secondary Data: Using existing data generated by large government Institutions, healthcare facilities etc. as part of organizational record keeping. The data is then extracted from more varied data files. Example Review articles, Books.
Supplementary Data: A few years ago the Obama Administration judged that any research that is done using Federal Public funds should be available for free to the public. Moreover Data Management Plans should be in place to store and preserve the data for almost eternity. These data sets are published as Supplementary Materials in the journal literature, and data sets can downloaded and manipulated for research.
NOTE: Even though the research is Primary source, the supplemental files downloaded by others becomes Secondary Source.Example:
If a published article has Supplementary Material, Supplemental Data, where can you find it?
Here are the steps to perform: Search for the published article page. On the article page (abstract or full text), look at the right hand side of the screen, where a dedicated section called "Supplemental Data" will list the different files:
Pros and Cons for each.
| BASIS FOR COMPARISON | PRIMARY DATA | SECONDARY DATA |
|---|---|---|
| Meaning | Primary data refers to the first hand data gathered by the researcher himself. | Secondary data means data collected by someone else earlier. |
| Data | Real time data | Past data |
| Process | Very involved | Quick and easy |
| Source | Surveys, observations, experiments, questionnaire, personal interview, etc. | Government publications, websites, books, journal articles, internal records etc. |
| Cost effectiveness | Expensive | Economical |
| Collection time | Long | Short |
| Specific | Always specific to the researcher's needs. | May or may not be specific to the researcher's need. |
| Available in | Crude form | Refined form |
| Accuracy and Reliability | More | Relatively less |
