Samitha - The general goal of grounded theory is to generate theories derived from data in order to understand the social context. The use of grounded theory help in providing useful data in original and rich research findings and theory because of its close tie to the data and the rigor in the method. Grounded theory could be one of the methodologies used for case study. The important reasons why the case study method is suitable for grounded theory: 1) the researcher can collect data and obtain evidence from a natural setting, then generate theories from practice; 2) the case study research method enables the researcher to answer “how” and “why” questions; 3) the case study method is an appropriate way to research an area in which few previous studies have been carried out. Triangulation is used to enhance the validity of research, the idea being that one can be more confident with a result if different methods lead to the same result.

Constructivist grounded theory can be used directly with case studies as the primary data. This would apply to any form of GT.

Alternatively, if you have already begun collecting data with individual participants, then you could consider doing cases studies as a form of "theoretical sampling" to help develop your emerging theory.

Thank you Dr. Hussain and Professor Morgan. Answers are really helpful.