So sánh phương pháp

	Phỏng vấn sâu theo chiều dọc	Khảo sát dọc
Lĩnh vực	Phương pháp luận khảo sát	Phương pháp luận khảo sát
Họ	Process / pipeline	Process / pipeline
Năm ra đời	1990s–2000s (as a formalised qualitative method)	1940s (panel survey tradition); longitudinal designs codified mid-20th century
Người khởi xướng	Rooted in qualitative longitudinal research traditions; systematised by Johnny Saldana	Established tradition; formalized in social science by Paul Lazarsfeld and colleagues (1940s panel studies)
Loại	Qualitative longitudinal data collection technique	Quantitative / mixed-methods survey design
Công trình gốc	Saldana, J. (2003). Longitudinal Qualitative Research: Analyzing Change Through Time. AltaMira Press. ISBN: 978-0759103917	Menard, S. (2002). Longitudinal Research (2nd ed.). Sage Publications. ISBN: 978-0761922292
Tên gọi khác	repeated in-depth interview, longitudinal qualitative interview, panel qualitative interview, longitudinal IDI	panel survey, repeated-measures survey, longitudinal panel study, wave survey
Liên quan	5	3
Tóm tắt	Longitudinal in-depth interviewing is a qualitative data collection technique in which the same participants are interviewed in depth on multiple occasions across a defined time span. By revisiting the same people over weeks, months, or years, researchers can trace how experiences, identities, attitudes, and meanings change — something a single interview cannot reveal. It is widely used in life-course research, health studies, education, and social policy.	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.