So sánh phương pháp

	Kỹ thuật Delphi	Khảo sát dọc	Nghiên cứu phương pháp hỗn hợp
Lĩnh vực	Phương pháp luận khảo sát	Phương pháp luận khảo sát	Định tính
Họ	Process / pipeline	Process / pipeline	Process / pipeline
Năm ra đời	1950s–1963	1940s (panel survey tradition); longitudinal designs codified mid-20th century	—
Người khởi xướng	Norman Dalkey and Olaf Helmer (RAND Corporation)	Established tradition; formalized in social science by Paul Lazarsfeld and colleagues (1940s panel studies)	—
Loại	Iterative expert consensus technique	Quantitative / mixed-methods survey design	Research design framework
Công trình gốc	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	Creswell, J.W. & Plano Clark, V.L. (2018). Designing and Conducting Mixed Methods Research (3rd ed.). Sage. ISBN: 978-1483344379
Tên gọi khác	Delphi method, Delphi survey, expert consensus method, iterative expert panel	panel survey, repeated-measures survey, longitudinal panel study, wave survey	Karma Yöntem Araştırması (Mixed Methods), multi-method research, triangulation design
Liên quan	6	3	4
Tóm tắt	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.	Mixed methods research is a systematic research design in which quantitative and qualitative data are collected and analysed within a single study. Formalised by Creswell and Plano Clark (2003, 3rd ed. 2018), it offers three principal design variants — concurrent, sequential, and transformative — and strengthens findings through triangulation across both data strands.