เปรียบเทียบวิธี

	การศึกษาเชิงนิเวศแบบย้อนหลัง	การศึกษาทางระบาดวิทยาภาคตัดขวาง
สาขาวิชา	ระบาดวิทยา	ระบาดวิทยา
ตระกูล	Process / pipeline	Process / pipeline
ปีกำเนิด	20th century (formalized ~1980s–1990s)	1960s (formal codification); widely practiced since mid-20th century
ผู้ริเริ่ม	Epidemiological tradition; formalized by Morgenstern and others	Classical epidemiology tradition; systematized by Brian MacMahon and Thomas Pugh (1960s)
ประเภท	Observational epidemiological design	Observational, descriptive/analytic epidemiological design
แหล่งต้นตำรับ	Morgenstern, H. (1998). Ecologic studies. In K. J. Rothman & S. Greenland (Eds.), Modern Epidemiology (2nd ed., pp. 459–480). Lippincott-Raven.	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
ชื่อเรียกอื่น	retrospective aggregate study, historical ecological study, retrospective correlational ecological design, population-level retrospective study	prevalence study, cross-sectional survey, transversal study, cross-sectional design
ที่เกี่ยวข้อง	5	6
สรุป	A retrospective ecological study examines associations between exposures and outcomes using pre-existing aggregate data from defined populations or geographic units. Rather than following individual subjects, the unit of analysis is a group — a country, region, or time period — and all measurements come from historical records already collected before the study began. It is a rapid, low-cost way to generate hypotheses about environmental, social, or policy determinants of disease at the population level.	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.