Qualitative analyses typically require a smaller sample size the quantitative analyses. Qualitative sample sizes should be large enough to obtain feedback for most or all perceptions. Obtaining most or all of the perceptions will lead to the attainment of saturation. Saturation occurs when adding more participants to the study does not result in additional perspectives or information. Glaser and Strauss (1967) recommend the concept of saturation for achieving an appropriate sample size in qualitative studies. Other guidelines have also been recommended. For an ethnography, Morse (1994) suggests approximately 30 - 50 participants. For grounded theory, Morse (1994) has suggested 30 - 50 interviews, while Creswell (1998) suggests only 20 - 30. And for phenomenological studies, Creswell (1998) recommends five to 25 and Morse (1994) suggests at least six. There are no specific rules when determining an appropriate sample size in qualitative research. Qualitative sample size may best be determined by the time allotted, resources available, and study objectives (Patton, 1990).
In general, qualitative research generates rich, detailed and valid process data that contribute to the in-depth understanding of a context. Quantitative research, on the other hand, generates reliable population-based and generalizable data that is suited to establishing cause-and-effect relationships. The decision of whether to choose a quantitative or a qualitative design is ultimately a philosophical question. Which methods to choose will depend on the nature of the project, the type of information needed the context of the study and the availability of resources (time, money, and human).