Compare to the quantitative research, the sampling procedures in qualitative research are not well defined. Selection of participants in qualitative research depends on the purpose of the research and is found to rely heavily on the researcher’s discretion. This flexibility in the procedure of sampling in qualitative has led to confusion to some researchers and increases the chances of mistakes (Morse, 1991). Quantitative techniques, however, rely on randomly selected, larger samples. The sampling techniques and logic behind each approach tend to be unique as the purpose of each strategy is different. The logic of probability or random sampling techniques of quantitative research depends on selecting a statistically representative sample from a larger population to get the generalized results.
Citing an instance where a researcher employed random sampling in qualitative research, Morse stated that it violates the principles of sampling method of quantitative research that requires ‘an adequate sample size in order to ensure representativeness and the qualitative principle of appropriateness that requires purposeful sampling and a “good” informant” (Morse, 1991, p.127). A good informant is the one who is articulate, reflective and is interested in sharing the information with the interviewers. Qualitative research focuses in-depth on small samples, even a single sampling unit (n = 1), selected purposefully for the study (Patton, 1990). The reliability and generalizability of the findings of qualitative research rely heavily on the information provided by the participants of the sample. Studies have been criticised for not describing in detail the procedure by which respondent is selected which makes the interpretation of the results difficult and also affects the replication of the study (Kitson et al. 1982). To establish rigour and credibility in qualitative studies it is the responsibility of the researcher to select the right technique of sampling (Lowenberg 1993, Sandelowski 1993, 1995).
The chapter intends to discuss the complexity associated with sampling procedure in qualitative research. The different types of sampling techniques used in qualitative research will also be explained to facilitate selection of right kind of sampling technique for the qualitative studies.