Sampling in qualitative research: A Guide for beginning

Sampling in qualitative and quantitative research are very different، because it aims، gaining a deep understanding of the phenomenon is being investigated، rather than generalizing the results. Participants Selection in the qualitative study is done with aim of achieve the maximum information about the phenomenon under study. In quantitative research there is too much emphasis on a random selection، an equal chance for selection of all members of the research community، but in the qualitative study samples or participants are selected or invited. Purposive sampling that also is called purposeful or qualitative sampling that means purposeful selection of samples for acquiring knowledge or information. This type of sampling does not focus on developing the fixed and immutable rules or generalizing the results but try to better understand the phenomenon in special field. Purposive sampling consists of three main types including «Sampling to Achieve Representativeness or Comparability»، «Sampling Special or Unique Cases» and «Sequential Sampling». Saturation in qualitative research as a method of sampling is considered the gold standard. In this paper، we tried to introduce the participant’s selection methods and the differences between quantitative and qualitative method and the strategy for decision making about data saturation will be offered.