手法を比較

	デルファイ法	フォーカスグループリサーチ	構造化合意形成手法としてのナショナル・グループ・テクニック（NGT）
分野	調査方法論	質的手法	質的手法
系統	Process / pipeline	Process / pipeline	Process / pipeline
提唱年	1950s–1963	1940s (sociological origin); modern applied form from the 1980s–1990s	1971
提唱者	Norman Dalkey and Olaf Helmer (RAND Corporation)	Robert K. Merton (sociological precursor, 1940s); popularised in applied research by Richard A. Krueger	André L. Delbecq and Andrew H. Van de Ven
種類	Iterative expert consensus technique	Qualitative data collection method	Qualitative research method
原典	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	Delbecq, A. L., & Van de Ven, A. H. (1971). A group process model for problem identification and program planning. Journal of Applied Behavioral Science, 7(4), 466–492.
別名	Delphi method, Delphi survey, expert consensus method, iterative expert panel	focus group discussion, FGD, group interview, Odak Grup Araştırması	NGT, structured group process, nominal group process, priority-setting group method
関連	6	6	6
概要	The Delphi technique is a structured, multi-round data collection method that harvests and refines expert opinion through iterative questionnaires and controlled feedback. Developed at RAND Corporation in the 1950s, it is designed to converge a dispersed expert panel toward a reliable consensus on complex, uncertain, or future-oriented questions — without the conformity pressures of face-to-face group discussion.	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.	The Nominal Group Technique (NGT) is a structured group facilitation method designed to generate and prioritise ideas, problems, or solutions while ensuring equal participation from all members. Developed by Delbecq and Van de Ven in 1971, it combines silent individual idea generation with structured group discussion and systematic voting to produce a ranked list of priorities. Unlike unstructured focus groups, NGT prevents dominant voices from suppressing quieter participants, making it especially valuable for needs assessment, program planning, and stakeholder priority-setting in applied research and policy contexts.