手法を比較

	Delphi Method	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	質的手法	質的手法
系統	Process / pipeline	Process / pipeline
提唱年	1963	1971
提唱者	Norman Dalkey & Olaf Helmer (RAND Corporation)	André L. Delbecq and Andrew H. Van de Ven
種類	Structured iterative expert-elicitation process	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.	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 Yöntemi, Delphi technique, expert consensus method	NGT, structured group process, nominal group process, priority-setting group method
関連	5	6
概要	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.	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.