Constant Comparative Method - Grounded Theory


The goal of the Grounded Theory approach is to generate theories that explain how some aspect of the social world 'works.' The goal is to develop a theory that emerges from and is therefore connected to the reality the theory is developed to explain. 

The contant comparative method is a method for analyzing data in order to develop a grounded theory.  Glaser and Strauss (1967) suggest that when used to generate theory, the comparative analytical method they describe can be applied to social units of any size.

As Glaser and Strauss (1967, pp. 28-52) describe it, this process involves:

Identifying a phenomenon, object, event or setting of interest

Identifying a few local concepts, principles, structural or process features of the experience or phenomenon of interest

Making decisions regarding initial collection of data based one's initial understanding of the phenomenon. Further data collection cannot be planned in advance of analysis and the emergence of theory

Engaging in theoretical sampling -- the key question is what group or subgroups does the researcher turn to next to collect data?  Subsequent sampling decisions should be purposeful and relevant. 

The rationale for selecting comparision groups is their theoretical relevance for fostering the development of emergent categories.

Coding procedures in Grounded Theory Approaches

Strauss and Corbin (1990) describe some flexible guidelines for coding data when engaging in a Grounded Theory analysis:

  • Open Coding -  "The process of breaking down, examining, comparing, conceptualizing, and categorizing data" (p. 61).
  • Axial Coding - "A set of procedures whereby data are put back together in new ways after open coding, by making connections between categories.  This is done by utilizing a coding paradigm involving conditions, context, action/interactional strategies and consequences" (p. 96).
  • Selective Coding - "The process of selecting the core category, systematically relating it to other categories, validating those relationships, and filling in categories that need further refinement and development" (p. 116).

During the analysis process, data coding will guide subsequent theoretical sampling decisions. 

After collecting additional data, the researchers return to analyzing and coding data, and use the insights from that analysis process to inform the next iteration of data collection. 

This process continues until a strong theoretical understanding of an event, object, setting or phenomenon has emerged.


Glaser, BG. & Strauss, AL. (1967). The Discovery of Grounded Theory: Strategies for Qualitative Research. New York: Aldine De Gruyter.

Strauss, A. & Corbin, J. (1990). Basics of Qualitative Research: Grounded Theory Procedures and Techniques. Newbury Park, CA: Sage Publications.

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