Classic Grounded Theory — Classic (Glaserian) Grounded Theory

Classic (Glaserian) GT holds that theory must emerge from data through constant comparison and theoretical sampling; the researcher should avoid prior literature and preconceived frameworks. Straussian GT (Strauss & Corbin, 1990) introduced axial coding — a structured procedure for specifying conditions, actions, and consequences — and shifted the method toward systematic verification. Glaser argued that axial coding forces the data into a pre-given framework, distorting emergence. The two variants share data-collection techniques but differ fundamentally in analytic logic and epistemological assumptions.

Classic GT does not prescribe a fixed sample size. Sampling is theoretical — driven by conceptual needs of the emerging theory — and continues until saturation: new data produce no new properties or dimensions of the core categories. Studies typically involve 20–50 participants, but the number is secondary to the criterion that categories are fully developed and saturated.

Glaser advises delaying a formal literature review so that prior theory does not force the data. In practice, complete ignorance of a field is impossible and may be undesirable. The key principle is that the literature should not determine which categories are important — the data should. Many researchers read broadly before the study but defer a focused review of directly relevant theory until after the core category has emerged, then use the literature as additional data to compare with the emerging theory.

The core category is the central concept that accounts for most variation in the data, recurs frequently, connects to other categories, and relates to what participants are most concerned about. Glaser suggested it should explain the main concern or basic social process. Identifying it typically happens during selective coding, once open coding and memo writing have generated a rich conceptual landscape. Indicators that a concept is the core category include its high frequency, its theoretical reach over other categories, and the sense that removing it would collapse the explanatory structure of the theory.

In principle, CGT can draw on any data that illuminates the process under study, including quantitative counts or survey results used as supplementary data. However, the primary analytic logic remains qualitative and conceptual. Integrating mixed methods substantially changes the research design and may require explicit justification within a broader framework such as convergent or exploratory sequential mixed methods. Pure CGT studies are typically fully qualitative.