Grounded theory is a qualitative research methodology that aims to build theory from data. It was developed by Glaser and Strauss in 1967. There are different approaches to grounded theory, including the Glaserian and Straussian approaches. The key processes in grounded theory include initial coding of data, focused coding to synthesize codes into categories, theoretical sampling to refine categories, and memo writing to develop theoretical concepts. Studies using grounded theory are critiqued based on their focus, methodology, sampling approach, data analysis process, and how well the theoretical findings are grounded in and link back to the data.