So sánh phương pháp

	Phỏng vấn bán cấu trúc 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 explicit methodology)	1940s (panel survey tradition); longitudinal designs codified mid-20th century
Người khởi xướng	Rooted in longitudinal qualitative research traditions; systematised by Johnny Saldana and Rachel Thomson & Janet Holland	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: 978-0759100480	Menard, S. (2002). Longitudinal Research (2nd ed.). Sage Publications. ISBN: 978-0761922292
Tên gọi khác	LSI, repeated semi-structured interview, panel qualitative interview, longitudinal qualitative interview	panel survey, repeated-measures survey, longitudinal panel study, wave survey
Liên quan	6	3
Tóm tắt	A longitudinal semi-structured interview study collects open-ended, guided interview data from the same participants across multiple time points. By returning to the same individuals — weeks, months, or years apart — researchers can trace how experiences, perceptions, and meanings change over time. The approach blends the flexibility of qualitative inquiry with the temporal depth that is impossible in a one-shot design, making it a cornerstone method in qualitative longitudinal research.	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.