Overview
Qualitative research designs fail when researchers apply quantitative validity criteria — complaining that the sample is too small, demanding representative sampling, or dismissing findings because they can't be generalized to a population. These criteria are epistemologically inappropriate for qualitative research, which seeks depth, meaning, and process understanding from purposively selected cases rather than statistical generalization from representative samples. Qualitative research has its own rigor standards: transferability, credibility, dependability, and confirmability — which apply depth criteria rather than breadth criteria.
The Qualitative Methodology Framework selects the appropriate qualitative tradition for the research question, applies purposive sampling with theoretical saturation logic, and builds a rigor framework using Lincoln and Guba's qualitative-appropriate criteria.