手法を比較

	パイロット理論的サンプリング	Grounded Theory	スノーボールサンプリング（またはチェーン紹介サンプリング）
分野	調査方法論	質的研究	調査方法論
系統	Process / pipeline	Process / pipeline	Process / pipeline
提唱年	1967 (theoretical sampling origin); compound practice formalized in qualitative methodology literature	1967	1961
提唱者	Glaser & Strauss (theoretical sampling); pilot study concept is longstanding in research methodology	Barney Glaser and Anselm Strauss	Leo A. Goodman
種類	Qualitative sampling strategy with pilot phase	Method	Non-probability sampling technique
原典	Glaser, B. G., & Strauss, A. L. (1967). The Discovery of Grounded Theory: Strategies for Qualitative Research. Aldine. ISBN: 978-0202302607	Glaser, B. G., & Strauss, A. L. (1967). The discovery of grounded theory: Strategies for qualitative research. Aldine.	Goodman, L. A. (1961). Snowball sampling. Annals of Mathematical Statistics, 32(1), 148–170.
別名	pilot-phase theoretical sampling, exploratory theoretical sampling, preliminary theoretical sampling	GT, Grounded Theory Approach	chain-referral sampling, network sampling, respondent-driven sampling, referral sampling
関連	3	3	3
概要	Pilot theoretical sampling applies the logic of theoretical sampling — selecting participants based on emerging concepts and theory — within a deliberate pilot or preliminary phase of a study. Rather than committing immediately to a full sampling strategy, the researcher conducts a small initial round of data collection and analysis to test whether theoretical sampling is feasible, to refine the sensitizing concepts guiding participant selection, and to identify whether the field is productive before full-scale data collection begins.	Grounded Theory (GT) is a systematic qualitative research methodology in which theory emerges directly from data through iterative analysis, rather than being imposed before data collection. Developed by Barney Glaser and Anselm Strauss in 1967, GT prioritizes generating explanatory frameworks grounded in evidence.	Snowball sampling is a non-probability recruitment technique in which initial participants (seeds) refer the researcher to others who meet the study criteria, and those referrals in turn refer further participants. The sample grows incrementally — like a rolling snowball — until the required size or theoretical saturation is reached. It is the method of choice when a target population has no accessible sampling frame, such as undocumented migrants, illicit drug users, survivors of stigmatised experiences, or members of closed professional networks.