手法を比較

	電話支援型デルファイ法	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
系統	Process / pipeline	Process / pipeline
提唱年	1963 (Delphi); telephone-assisted variant prominent 1970s–1990s	1971
提唱者	Norman Dalkey & Olaf Helmer (RAND Corporation); telephone adaptation used throughout 1970s–1990s applied research	André L. Delbecq and Andrew H. Van de Ven
種類	Iterative expert consensus technique delivered by telephone	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	telephone Delphi, phone-based Delphi, CATI Delphi, telephone consensus method	NGT, structured group process, nominal group process, priority-setting group method
関連	4	6
概要	The telephone-assisted Delphi Technique applies the classic iterative expert-consensus framework through structured telephone interviews rather than mailed or online questionnaires. Experts participate in sequential rounds of data collection by phone, enabling the researcher to clarify ambiguous responses in real time and reach consensus on complex, contested, or forward-looking questions without requiring participants to convene in person.	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.