Comparer des méthodes

	Case Study	Méthode Delphi	Recherche par groupes de discussion
Domaine	Qualitatif	Qualitatif	Qualitatif
Famille	Process / pipeline	Process / pipeline	Process / pipeline
Année d'origine	1984 (seminal codification)	1963	1940s (sociological origin); modern applied form from the 1980s–1990s
Auteur d'origine	Robert K. Yin (systematised in Case Study Research, 1984)	Norman Dalkey & Olaf Helmer (RAND Corporation)	Robert K. Merton (sociological precursor, 1940s); popularised in applied research by Richard A. Krueger
Type	Qualitative research design	Structured iterative expert-elicitation process	Qualitative data collection method
Source fondatrice	Yin, R.K. (2018). Case Study Research and Applications: Design and Methods (6th ed.). Sage. ISBN: 978-1506336169	Dalkey, N. & Helmer, O. (1963). An Experimental Application of the Delphi Method to the Use of Experts. Management Science, 9(3), 458-467.	Krueger, R.A. & Casey, M.A. (2014). Focus Groups: A Practical Guide for Applied Research (5th ed.). Sage. ISBN: 978-1483365244
Alias	Vaka Çalışması (Case Study), case study design, case study methodology	Delphi Yöntemi, Delphi technique, expert consensus method	focus group discussion, FGD, group interview, Odak Grup Araştırması
Apparentées	5	5	6
Résumé	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.	The Delphi method is a structured, iterative survey technique developed by Norman Dalkey and Olaf Helmer at the RAND Corporation in 1963 for eliciting and converging expert opinion on complex topics where empirical data are unavailable or insufficient. It collects independent judgements from a geographically dispersed expert panel over multiple anonymous rounds, feeding aggregated results back to participants after each round so they can revise their views in light of the group's collective position.	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.