방법 비교

	종단 연구	트렌드 연구
분야	연구설계	연구설계
계열	Process / pipeline	Process / pipeline
기원 연도	Late 19th–early 20th century; methodologically codified through the 20th century	Mid-20th century (formalised in social science methodology ~1950s–1960s)
창시자	No single originator; foundational methodological treatments by Stuart Menard and Judith Singer & John Willett	Earl Babbie and survey research tradition
유형	Quantitative (or mixed) observational research design	Quantitative longitudinal research design
원전	Menard, S. (2002). Longitudinal Research (2nd ed.). Sage Publications. ISBN: 978-0761922841	Creswell, J. W. (2014). Research Design: Qualitative, Quantitative, and Mixed Methods Approaches (4th ed.). Sage. ISBN: 978-1452226101
별칭	longitudinal study, longitudinal design, prospective longitudinal study, repeated-measures observational study	trend study, trend survey, longitudinal trend study, time-series survey
관련	4	4
요약	Longitudinal research is an observational design in which the same participants, groups, or units are measured repeatedly over an extended period. Rather than capturing a single snapshot, it tracks change, stability, and temporal sequencing of variables — making it the primary non-experimental strategy for studying development, growth, decline, and the unfolding of causal processes across time.	Trend research is a longitudinal quantitative design that tracks changes in a characteristic of a general population over time by surveying different, independently drawn samples at two or more time points. Unlike panel studies, the same individuals are not followed; rather, each wave draws a fresh sample from the same population, allowing researchers to detect population-level shifts in attitudes, behaviours, or conditions while avoiding the attrition and panel conditioning problems of repeated-measures designs.