Confronta i metodi

	Indagine	Tecnica Delphi	Indagine Longitudinale
Campo	Metodologia delle indagini	Metodologia delle indagini	Metodologia delle indagini
Famiglia	Process / pipeline	Process / pipeline	Process / pipeline
Anno di origine	Late 19th century; systematic social-science use from 1940s	1950s–1963	1940s (panel survey tradition); longitudinal designs codified mid-20th century
Ideatore	Francis Galton, Charles Booth, and early social statisticians; formalised by Paul Lazarsfeld in the 1940s	Norman Dalkey and Olaf Helmer (RAND Corporation)	Established tradition; formalized in social science by Paul Lazarsfeld and colleagues (1940s panel studies)
Tipo	Quantitative (primarily) or mixed-methods data-collection instrument	Iterative expert consensus technique	Quantitative / mixed-methods survey design
Fonte seminale	Dillman, D. A., Smyth, J. D., & Christian, L. M. (2014). Internet, Phone, Mail, and Mixed-Mode Surveys: The Tailored Design Method (4th ed.). Wiley. ISBN: 978-1118456149	Dalkey, N., & Helmer, O. (1963). An experimental application of the Delphi method to the use of experts. Management Science, 9(3), 458–467.	Menard, S. (2002). Longitudinal Research (2nd ed.). Sage Publications. ISBN: 978-0761922292
Alias	questionnaire survey, survey research, self-report survey, questionnaire study	Delphi method, Delphi survey, expert consensus method, iterative expert panel	panel survey, repeated-measures survey, longitudinal panel study, wave survey
Correlati	6	6	3
Sintesi	A survey is a systematic data-collection method in which a standardised set of questions is posed to a sample of respondents to measure attitudes, behaviours, demographics, or other constructs. Surveys can be administered via paper, telephone, online platforms, or face-to-face. They are among the most widely used instruments in social, behavioural, health, and educational research because they can reach large, geographically dispersed samples at relatively low cost.	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 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.