So sánh phương pháp

	Phỏng vấn bán cấu trúc theo chiều dọc	Nhóm tập trung 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 (focus groups); longitudinal variant refined 1980s–1990s
Người khởi xướng	Rooted in longitudinal qualitative research traditions; systematised by Johnny Saldana and Rachel Thomson & Janet Holland	Adapted from Robert K. Merton's focused interview tradition; longitudinal design developed in social and health sciences
Loại	Qualitative longitudinal data collection technique	Qualitative longitudinal data collection
Công trình gốc	Saldana, J. (2003). Longitudinal Qualitative Research: Analyzing Change Through Time. AltaMira Press. ISBN: 978-0759100480	Morgan, D. L. (1997). Focus Groups as Qualitative Research (2nd ed.). Sage Publications. ISBN: 978-0761903437
Tên gọi khác	LSI, repeated semi-structured interview, panel qualitative interview, longitudinal qualitative interview	repeated focus group, panel focus group, longitudinal FG, follow-up focus group
Liên quan	6	5
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 focus group convenes the same group of participants in multiple sessions over an extended period — weeks, months, or years — to trace how their attitudes, experiences, or interpretations evolve in response to changing circumstances. Unlike a single focus group snapshot, the repeated-contact design captures the dynamics of opinion and meaning-making across time, making it particularly valuable in health, policy, and social research where change is the phenomenon of interest.