手法を比較

	質的研究におけるデータ飽和	フォーカスグループ・方法論
分野	質的研究	質的研究
系統	Process / pipeline	Process / pipeline
提唱年	1967	1956
提唱者	Barney Glaser and Anselm Strauss	Robert K. Merton and Paul F. Lazarsfeld
種類	Concept	Method
原典	Glaser, B. G., & Strauss, A. L. (1967). The Discovery of Grounded Theory: Strategies for Qualitative Research. Aldine. ISBN: 978-0202302560	Krueger, R. A. (1994). Focus Groups: A Practical Guide for Applied Research. SAGE Publications. ISBN: 978-0803954366
別名	saturation, theoretical saturation, thematic saturation, sampling to saturation	FGD, focus group discussion, group interview
関連	4	4
概要	Data saturation is a foundational principle in qualitative research describing the point at which data collection yields no new themes, codes, or insights—additional data becomes redundant. Introduced by Glaser and Strauss (1967) in their work on grounded theory, saturation guides decisions about sample size and when to stop recruiting participants. Saturation is not a fixed number but a dynamic endpoint determined by examining whether new data are adding substantively new information. The concept is central to claims of rigor and theoretical adequacy in qualitative research, signaling that the researcher has gathered sufficient data to understand the phenomenon in depth.	Focus group discussions are a qualitative research method in which a trained moderator guides a small group (typically 6–12 participants) through structured or semi-structured discussion of a specific topic or product. Developed by Merton and Lazarsfeld in the 1950s for market research, focus groups are now widely used in health sciences, education, social sciences, and policy research. The method leverages group interaction to generate rich, contextual insights that individual interviews may not reveal.