Ethnography
The emphasis in ethnography is on studying an entire culture. Originally, the idea of a culture was tied to the notion of ethnicity and geographic location, but it has been broadened to include virtually any group or organization. That is, we can study the "culture" of a business or defined group.
The most common ethnographic approach is participant observation as a part of field research. The ethnographer becomes immersed in the culture as an active participant and records extensive field notes. As in grounded theory, there is no preset limiting of what will be observed and no real ending point in an ethnographic study.
Field Research
Field research can be considered either a broad approach to qualitative research or a method of gathering qualitative data. The essential idea is that the researcher goes "into the field" to observe the phenomenon in its natural state. It is the method of participant observation. The field researcher typically takes extensive field notes which are subsequently coded and analyzed in a variety of ways.
Grounded Theory
The purpose of grounded theory is to develop theory about phenomena of interest. But this is not just abstract theorizing, the theory needs to be grounded or rooted in observation. It is a complex iterative process. The research begins with the raising of generative questions which help to guide the research but are not intended to be either static or confining. As the researcher begins to gather data, core theoretical concept(s) are identified. Tentative linkages are developed between the theoretical core concepts and the data. This early phase of the research tends to be very open and can take months. Later on the researcher is more engaged in verification and summary. The effort tends to evolve toward one core category that is central.
Phenomenology
Phenomenology is sometimes considered a philosophical perspective as well as an approach to qualitative methodology. It has a long history in several social research disciplines including psychology, sociology and social work. Phenomenology emphasizes a focus on people's subjective experiences and interpretations of the world. The phenomenologist wants to understand how the world appears to others.