All research is "grounded" in data, but few studies produce a "grounded theory." Grounded Theory is an inductive methodology. Although many call Grounded Theory a qualitative method, it is not. It is a general method. It is the systematic generation of theory from systematic research. It is a set of rigorous research procedures leading to the emergence of conceptual categories. These concepts/categories are related to each other as a theoretical explanation of the action(s) that continually resolves the main concern of the participants in a substantive area. Grounded Theory can be used with either qualitative or quantitative data.
Source: Grounded Theory Institute http://www.groundedtheory.org/what-is-gt.aspx
Dr. Barney Glaser, cofounder of grounded theory, discusses grounded theory as the study of a concept
What is it?
From Analysing Qualitative Data by Graham R. Gibbs (2007): "Grounded theory is an inductive form of qualitative research, introduced by sociologists Barney Glaser and Anselm Strauss, where data collection and analysis are conducted together. Constant comparison and theoretical sampling are used to support the systematic discovery of theory from the data. Thus theories remain grounded in the observations rather than generated in the abstract. Sampling of cases, settings or respondents is guided by the need to test the limits of developing explanations which are constantly grounded in the data being analysed."
Strauss and Corbin (1990) suggest there are 3 stages in analysis in grounded theory: open coding, axial coding and selective coding. During open coding the researcher reads the text and identifies codes based on observations of the data (not pre-determined labels). In axial coding, the researcher identifies relationships between the data. Selective coding identifies the one core category or label that drives the rest of the data. Here, you'll consider the underlying intentions and meanings to uncover one essential concept that grounds the rest of the data. Researcher Tiffany Gallicano illustrates this process in this chart:
For further reading, Dr. Gallicano's blog is available here.
Constant comparison
This involves various methods of constant comparison. Previously coded text also needs to be checked to see if the new codes created are relevant. Constant comparison is a central part of grounded theory. Newly gathered data are continually compared with previously collected data and coding in order to refine the development of theoretical categories. The purpose is to test emerging ideas that might take the research in new and fruitful directions.
Coding Line-by-line
Another approach used in grounded theory is line-by-line coding, which literally means coding each line of an interview. This approach is intended to keep the researcher close to the data while forcing them to be analytical. The researcher must think carefully about what the person being interviewed is literally saying and also consider the meaning behind the statements. Line-by-line coding is intended to prevent a researcher's analysis from being influenced by preconceived ideas or mere acceptance of the interviewee's point of view.
Source: Online QDA
Transformational change in parenting practices after child interpersonal trauma: A grounded theory examination of parental response
Veteran identity as a protective factor: A grounded theory comparison of perceptions of self, illness, and treatment among veterans and non-veterans with schizophrenia
Disembedding the Traditional Family: Grounded Theory and the Study of Family Change among Mangor and Gaverk Tribes of Iranian Kurdistan