Multiple Case-Based Classic Grounded Theory

A comparative case study aims to produce rich, contextualised descriptions of each case and then compare findings across cases — the case is the unit of analysis and the product. Multiple case-based classic GT uses cases as vehicles for generating concepts and categories; the emerging theory — not the cases themselves — is the end product. Cross-case comparison in GT is an analytic engine, not a reporting format.

Classic GT does not specify a minimum number of cases in advance. Two to six cases is common in practice, but the guiding principle is theoretical saturation: you continue adding cases (or deepening data within cases) until no new properties of the core category are emerging. If saturation is reached with two cases, two is sufficient; if gaps persist after six, more cases or new data sources are warranted.

Glaser's classic position is that the researcher should delay extensive literature review until the core category has emerged, to avoid contaminating the inductive process with existing concepts. In practice, many researchers conduct a scoping review for feasibility and ethics purposes but deliberately set aside theoretical frameworks during data collection and early coding. The key is that the theory must emerge from the data, not from the literature.

Classic (or Glaserian) GT stays closest to the original 1967 framework: it insists on pure emergence of categories (no forcing), uses all-is-data as the coding stance, emphasises theoretical memos, and has a specific set of coding families for developing categories. Strauss and Corbin's later version introduced axial coding and a conditional matrix that Glaser considered overly prescribed. Constructivist GT (Charmaz) adds a social constructionist epistemology. The classic variant remains purely inductive and emergence-driven.

The report centres on the substantive theory, not on sequential case narratives. Present the core category and its properties, explain how supporting categories relate to it, and illustrate the theory with incident-level examples drawn from across cases. A diagram showing the theoretical model and its category relationships is standard. Individual case descriptions are typically confined to a methods section or appendix to orient readers to the empirical contexts.