| name | sampling-strategies |
| description | Use when selecting sampling strategies for qualitative research — purposeful, theoretical, snowball, criterion, maximum variation. |
Sampling Strategies in Qualitative Research
Qualitative sampling prioritizes information-rich cases and analytic progression over statistical representativeness. Your sampling chapter should explain logic, not pretend to randomize for generalization in a positivist sense.
Purposeful sampling (Patton)
Purposeful sampling selects cases that illuminate the phenomenon intensely. Common variants:
- Maximum variation: Deliberately include diverse contexts to surface core patterns and boundaries.
- Homogeneous: Deepen understanding within a similar subset when noise reduction helps early theory.
- Typical case: Clarify the “usual” pattern when stakeholders misunderstand extremes.
- Critical case: A instance that can falsify or strongly test an emerging claim.
- Criterion: All participants meet explicit inclusion criteria tied to the research question.
- Snowball/chain: Referrals lead to new participants; efficient for hidden populations.
Theoretical sampling (Glaser)
After initial coding, theoretical sampling seeks data to elaborate properties, dimensions, conditions, and consequences of emerging categories. You sample for analytic gaps, not demographic quotas (unless demographics are theoretically relevant). The question is: “What data do I need next to develop this category?”
Snowball and chain referral sampling
Use when populations are hard to reach or trust is network-based. Mitigate bias from seed participants by using multiple entry points and monitoring whose voices dominate. Document referral chains in audit materials.
Maximum variation vs typical case
Maximum variation guards against provincial theory; typical case helps communicate mundane patterning. In GT, these are tools in service of emergent categories—choose based on what the evolving theory demands.
Convenience sampling (with caveats)
Convenience sampling is acceptable only when limitations are transparent and you take compensatory steps (prolonged engagement, triangulation, negative case search). Never dress convenience up as theoretical sampling without analytic justification.
Sample size in qualitative research
“How many?” depends on study scope, data richness, and saturation. A focused GT project may achieve workable saturation with fewer cases if incidents are dense; a comparative multi-site study may need many more. Report saturation reasoning and disconfirming efforts, not a fake power analysis.
Saturation-based sampling
Saturation means no new properties/dimensions are emerging for a category (in the Glaserian sense), not mere repetition of wordings. Track saturation by category, not only globally—some categories saturate early while others remain thin.
Integration tip
In proposals, distinguish initial purposeful sampling (who can get you started) from later theoretical sampling (who/what you need next as categories form). This shows methodological maturity in GT.
Checklist
References (starting points)
- Patton, M. Q. Qualitative research and evaluation methods — purposeful sampling typology.
- Glaser, B. G., & Strauss, A. L. The Discovery of Grounded Theory — theoretical sampling origins.
- Emmel, N. Sampling and choosing cases in qualitative research.