방법 비교

	회고적 코호트 연구	횡단면 역학 연구
분야	역학	역학
계열	Process / pipeline	Process / pipeline
기원 연도	Mid-20th century (widely formalized 1950s–1970s)	1960s (formal codification); widely practiced since mid-20th century
창시자	Systematic use attributed to early 20th-century occupational epidemiology; formalized in modern epidemiological theory by Brian MacMahon and others	Classical epidemiology tradition; systematized by Brian MacMahon and Thomas Pugh (1960s)
유형	Observational analytic study	Observational, descriptive/analytic epidemiological design
원전	Rothman, K. J., Greenland, S., & Lash, T. L. (2008). Modern Epidemiology (3rd ed.). Lippincott Williams & Wilkins. ISBN: 978-0781755641	Kelsey, J. L., Whittemore, A. S., Evans, A. S., & Thompson, W. D. (1996). Methods in Observational Epidemiology (2nd ed.). Oxford University Press. ISBN: 978-0195080407
별칭	historical cohort study, non-concurrent cohort study, retrospective follow-up study, historical prospective study	prevalence study, cross-sectional survey, transversal study, cross-sectional design
관련	6	6
요약	A retrospective cohort study assembles a group of individuals who share a common starting point and reconstructs their exposure history and subsequent outcomes entirely from pre-existing records. Because the data have already been collected before the study begins, the design is far faster and cheaper than a prospective cohort; however, the researcher must work with whatever information was recorded at the time rather than collecting purpose-built measurements.	A cross-sectional epidemiological study measures the exposure(s) and outcome(s) of interest simultaneously in a defined population at a single point in time (or over a short period). Because there is no follow-up, it is the most efficient observational design for estimating disease prevalence and for generating hypotheses about associations between risk factors and health outcomes.