手法を比較

	デルファイ法	対面調査	縦断調査
分野	調査方法論	調査方法論	調査方法論
系統	Process / pipeline	Process / pipeline	Process / pipeline
提唱年	1950s–1963	1930s–1940s (systematic survey era)	1940s (panel survey tradition); longitudinal designs codified mid-20th century
提唱者	Norman Dalkey and Olaf Helmer (RAND Corporation)	Established practice formalised in survey methodology (Gallup, Likert, and others from the 1930s–1940s)	Established tradition; formalized in social science by Paul Lazarsfeld and colleagues (1940s panel studies)
種類	Iterative expert consensus technique	Quantitative / mixed-mode data collection	Quantitative / mixed-methods survey design
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.	Fowler, F. J. (2014). Survey Research Methods (5th ed.). Sage Publications. ISBN: 978-1452259000	Menard, S. (2002). Longitudinal Research (2nd ed.). Sage Publications. ISBN: 978-0761922292
別名	Delphi method, Delphi survey, expert consensus method, iterative expert panel	personal interview survey, in-person survey, PAPI survey, door-to-door survey	panel survey, repeated-measures survey, longitudinal panel study, wave survey
関連	6	5	3
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.	A face-to-face survey is a structured data collection method in which a trained interviewer meets respondents in person and administers a standardised questionnaire. The interviewer reads questions aloud, clarifies wording when permitted by protocol, and records answers — either on paper (PAPI) or a laptop/tablet (CAPI). This mode consistently achieves higher response rates and better data quality for complex or sensitive questionnaires than self-administered alternatives, and is the reference standard in large-scale population surveys.	A longitudinal survey collects structured questionnaire data from the same individuals or units at two or more distinct points in time. By tracking the same respondents across waves, researchers can distinguish genuine change from stable individual differences, establish temporal ordering between variables, and model trajectories of attitudes, behaviors, or outcomes in ways that a single cross-sectional snapshot cannot support.