In grounded theory studies the changing nature of the researcher’s understanding of a phenomenon informs the changing nature of their sampling strategy during the lifetime of a project. A staged approach to sampling is undertaken with the intention of exploring a full range of experiences or data sets.
Initially, purposive sampling is used to select a subset of the defined population known to have knowledge or experience of the research phenomenon. Later, as the researcher’s understanding of the phenomenon develops, a move to theoretical sampling is made in support of the ongoing development of the grounded theory; the subset of the defined population shifts to one that can provide detailed, complex and contradictory accounts of the research topic.
Opinions differ about when to start theoretical sampling, ranging from the first occurrence of constant comparative analysis as the researcher follows-up areas of interest, to only having value in confirming, clarifying and expanding theoretical categories.
Acknowledging the aim of facilitating depth and richness in the data of a grounded theory study, theoretical sampling continues until theoretical saturation has been achieved, that is, when the theory’s categories and their properties have been clearly articulated.
References
Birks, M., & Mills, J. (2023). Grounded theory: a practical guide (3rd ed.). SAGE Publications Ltd.
Braun, V., & Clarke, V. (2013). Successful qualitative research: a practical guide for beginners. Sage.
Bryant, A., & Charmaz, K. (2007). The SAGE handbook of grounded theory. SAGE Publications Ltd.
Charmaz, K. (2014). Constructing grounded theory (2nd ed.). Sage.
Coyne, I. T. (1997). Sampling in qualitative research. Purposeful and theoretical sampling; merging or clear boundaries? Journal of Advanced Nursing, 26, 623-630.
Glaser, B. G. (1998). Doing grounded theory: issues and discussions. Sociology Press.
If you found The Grounded Theorist useful, and would like to ensure its continued availability, please consider making a one-off donation or becoming a sustaining member. Thank you.
The Grounded Theorist 