Longitudinal Straussian Grounded Theory

Glaserian grounded theory avoids imposing a preconceived analytic structure and emphasises emergence; Strauss and Corbin's version uses an explicit coding paradigm (conditions, context, action/interaction, consequences) to guide axial coding. Constructivist grounded theory (Charmaz) foregrounds the researcher's co-construction of meaning with participants. In longitudinal work, the Straussian paradigm's focus on conditions and consequences maps naturally onto temporal change, making it particularly tractable for multi-wave designs where tracing causal dynamics over time is the goal.

There is no fixed rule, but most longitudinal grounded theory studies use between two and five waves and begin with 15–30 participants, expecting some attrition. The criterion is theoretical saturation — continuing waves and sampling until new data no longer revise the theory. The interval between waves should reflect the natural pace of the phenomenon: rapidly shifting situations may warrant quarterly waves; slower social processes may require annual contact.

Yes, and this is increasingly common. Quantitative measures (surveys, administrative records) can be collected alongside qualitative interviews at each wave to contextualise the qualitative findings or to identify cases for theoretical sampling. However, the grounded theory component remains the primary theory-generating element; quantitative data serve an explanatory or sampling function rather than driving the analysis.

Attrition should be treated analytically, not merely statistically. Record who leaves, when, and if possible why. Ask whether non-completers shared distinctive characteristics — if so, consider whether the emerging theory accurately represents their trajectory. In some cases, early leavers may be theoretically sampled back in for a final interview. Report attrition transparently and reflect on its implications for the scope and transferability of the resulting theory.

Grounded theory is most appropriate when existing theory is absent, insufficient, or does not adequately explain the phenomenon from participants' perspectives. If a robust theory already exists and the goal is to test or extend it, other designs — such as theory-driven longitudinal qualitative research or mixed-methods longitudinal studies — may be more appropriate. Using grounded theory to reinvent a well-established explanatory framework wastes resources and dilutes the method's distinctive contribution.