เปรียบเทียบวิธี

	การวิจัยแบบกลุ่มสนทนา	การวิจัยกรณีศึกษา	ทฤษฎีฐานราก
สาขาวิชา	เชิงคุณภาพ	เชิงคุณภาพ	การวิจัยเชิงคุณภาพ
ตระกูล	Process / pipeline	Process / pipeline	Process / pipeline
ปีกำเนิด	1940s (sociological origin); modern applied form from the 1980s–1990s	1984 (seminal codification)	1967
ผู้ริเริ่ม	Robert K. Merton (sociological precursor, 1940s); popularised in applied research by Richard A. Krueger	Robert K. Yin (systematised in Case Study Research, 1984)	Barney Glaser and Anselm Strauss
ประเภท	Qualitative data collection method	Qualitative research design	Method
แหล่งต้นตำรับ	Krueger, R.A. & Casey, M.A. (2014). Focus Groups: A Practical Guide for Applied Research (5th ed.). Sage. ISBN: 978-1483365244	Yin, R.K. (2018). Case Study Research and Applications: Design and Methods (6th ed.). Sage. ISBN: 978-1506336169	Glaser, B. G., & Strauss, A. L. (1967). The discovery of grounded theory: Strategies for qualitative research. Aldine.
ชื่อเรียกอื่น	focus group discussion, FGD, group interview, Odak Grup Araştırması	Vaka Çalışması (Case Study), case study design, case study methodology	GT, Grounded Theory Approach
ที่เกี่ยวข้อง	6	5	3
สรุป	Focus group research is a qualitative data-collection method in which a trained moderator guides structured discussions with homogeneous groups of six to ten participants to explore ideas, attitudes, and perceptions on a defined topic. Developed from sociological roots in the 1940s and systematised for applied research by Krueger and Casey, the method leverages group interaction as a data source — revealing not just what people think, but how they negotiate and articulate views in a social setting.	Case study research is a qualitative research design that investigates a specific phenomenon, individual, group, organisation, or event in depth within its real-world context. Systematised by Robert K. Yin in 1984, it supports single-case and multiple-case designs and draws on multiple data sources — interviews, observation, documents, and artefacts — to build a rich, contextualised account of a bounded unit.	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.