Grounded theory is a qualitative research methodology in which a theory is built directly from data rather than tested against it. Instead of starting with a hypothesis and looking for confirmation, the researcher collects data, analyzes it, and lets explanatory concepts emerge, returning to gather more data to develop and refine those concepts until a coherent theory grounded in the evidence takes shape. It was developed by Glaser and Strauss in 1967 and remains the standard approach when the goal is to generate theory about a process for which little existing explanation fits.
The defining commitment is that the theory comes from the data. Grounded theory is not a way to organize interviews around themes you already expected; it is a disciplined process for discovering an explanation you did not have at the start. That ambition makes it powerful for under-theorized topics and demanding to execute well.
What makes grounded theory distinctive
Several interlocking features separate grounded theory from other qualitative methods.
Constant comparison runs throughout: every new piece of data is compared with existing codes and concepts, sharpening categories and revealing their properties. Theoretical sampling means later data collection is guided by the emerging theory, so you deliberately seek the participants or situations that will test and extend your developing concepts, rather than fixing the entire sample in advance. Memo writing captures the analyst's developing thinking, building the bridge from codes to theory. And data collection and analysis happen iteratively, in cycles, rather than as separate phases.
This iterative, theory-driven sampling is the clearest practical difference from a method such as thematic analysis, where data are usually collected first and analyzed afterward. In grounded theory the analysis shapes what you collect next.
The coding stages
Grounded theory analysis moves through coding stages that progressively build abstraction. Open coding breaks the data into discrete concepts, labeling what is happening line by line or incident by incident. Axial coding reassembles those concepts, identifying relationships among categories and their properties. Selective coding integrates everything around a central category that ties the theory together. Terminology varies across the main traditions, but the movement from concrete data to an integrated explanation is common to all.
The endpoint is theoretical saturation, the point at which gathering more data yields no new properties or insights about the categories. Saturation, not a predetermined sample size, governs when data collection stops, which is one reason grounded theory cannot specify its final sample in advance the way a survey can.
The major traditions
Grounded theory is not a single fixed recipe. After the original 1967 statement, its founders diverged: the Glaserian tradition emphasizes emergence and resists imposing structure, while the Straussian tradition, developed with Corbin, offers more prescribed coding procedures. Later, constructivist grounded theory, associated with Charmaz, foregrounds the researcher's role in co-constructing the analysis rather than treating theory as simply discovered in the data.
Naming the tradition you follow is not pedantry; it tells a reviewer which procedures and assumptions govern your study and which standards your work should be judged against. Choosing and justifying the right tradition for a research question is part of the methodological guidance our research methodology support provides.
Grounded theory reasons by abduction, not pure induction
The slogan that theory comes from the data invites a misunderstanding worth correcting, because examiners probe it. Grounded theory is not naive induction in which the analyst arrives empty-headed and reads a theory off the transcripts. Its actual engine is abduction: when the data show something surprising that existing concepts do not explain, the analyst forms a tentative explanation and then returns to the data to test and refine it. This cycle of constant comparison is a disciplined back-and-forth between observation and conjecture, not a one-way flow upward from raw text. Recognising abduction also resolves the most common confusion: a grounded theory is genuinely grounded when each conceptual claim can be traced to specific incidents in the data and was revised whenever the data resisted it, not when the researcher pretended to have no prior ideas at all.
The traditions differ in epistemology, not just procedure
The split between Glaser, Strauss and Corbin, and Charmaz is usually taught as different coding vocabularies, but the deeper difference is what each believes a theory is. The Glaserian (classic) tradition is broadly objectivist: the theory is discovered in the data, the analyst stays open and resists forcing, and coding moves from open coding to theoretical coding using "coding families." The Straussian tradition is pragmatist and more procedural, adding axial coding structured by a coding paradigm (conditions, actions and interactions, consequences) and a conditional or consequential matrix to situate the phenomenon in its context. Constructivist grounded theory (Charmaz) is relativist: the theory is co-constructed by a researcher who is part of the world studied, and its coding sequence is initial coding, then focused coding, then theoretical integration, with reflexivity treated as essential rather than as contamination. Choosing a tradition therefore commits you to an epistemology and a quality standard, and mixing the objectivist promise of discovery with constructivist co-construction in the same study is the kind of incoherence a methods-savvy reader will flag.