Theoretical sampling
Theoretical sampling refers to the process of choosing new research sites or cases to compare with ones that have already been studied. It is one of the tools of qualitative research. The term was coined by Barney Glaser and Anselm Strauss in 1967.
The goal of theoretical sampling is not the same as with the probabilistic sampling; the researcher's goal is not the representative capture of all possible variations, but to gain a deeper understanding of analysed cases and facilitate the development of analytic frame and concepts used in their research.
Theoretical sampling can be viewed as a technique of data triangulation: using independent pieces of information to get a better fix on something that is only partially known or understood.
Theoretical Saturation
The concept of saturation was first defined in the context of grounded theory as theoretical saturation. In qualitative research the word saturation is extensively used almost interchangeably with data saturation, thematic saturation, theoretical saturation and conceptual saturation. Saturation can be simply defined as data satisfaction. It is when the researcher reaches a point where no new information is obtained from further data.
Saturation point determines the sample size in qualitative research as it indicates that adequate data has been collected for a detailed analysis. However, there are no fixed sizes or standard tests that can determines the required data for reaching saturation.
See also
References
- Charles C. Ragin, 'Constructing Social Research: The Unity and Diversity of Method', Pine Forge Press, 1994, ISBN 0-8039-9021-9
- Barney G. Glaser & Anselm L. Strauss, 'The Discovery of Grounded Theory: Strategies for Qualitative Research', Chicago, Aldine Publishing Company, 1967, ISBN 0-202-30260-1