Primary Data & Secondary Data: Definition & Example

primary data
A door-to-door survey is one way to collect primary data.

Primary data is data that is collected by a researcher from first-hand sources, using methods like:

  • Creative works (paintings, movie reels, music etc.)
  • Diaries,
  • Experiments performed by you, the researcher,
  • Letters,
  • Surveys and censuses,
  • Interviews.

A primary source is collected directly from the original source. It is not clouded with someone else’s views or judgments.

The term is used in contrast with the term secondary data. Secondary data is data gathered from studies, surveys, or experiments that have been run by other people or for other research. Examples of secondary data include:

  • Encyclopedias,
  • Essays,
  • Newspaper opinion pieces,
  • Reviews,
  • Textbooks.

Typically, a researcher will begin a project by working with secondary data. This allows time to formulate questions and gain an understanding of the issues being dealt with before the more costly and time consuming operation of collecting primary data.

Example of Primary Data & Secondary Data

Let’s say you were researching trauma in burn survivors; You would typically begin your study by going through the literature on the subject. Data gleaned both from published papers and unpublished research notes would be secondary data. Although it isn’t primary data, it could give you invaluable information nonetheless. If you decided to go on to collect primary data, the secondary data would give you what information you need to know where to begin.

If you took a trip to a trauma unit and interviewed burn survivors, the data collected in that phase of your research would be primary data.

If one of your interviewees puts you in touch with a burn survivor support group, and you are given access to a database of information about the psychological state of a large group of survivors in the years following the burn incident, that would also be secondary, not primary, data.


Driscoll & Brizee. What is Primary Research? Purdue Online Write Lab. Retrieved from on June 24th, 2017
BYU FHSS Research Support Center. Data Types and Sources. Retrieved from on June 24th, 2018
Yin, R. (2017). Case Study Research and Applications: Design and Methods 6th Edition. SAGE Publications.

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