手法を比較

	生態学的研究	横断疫学研究
分野	疫学	疫学
系統	Process / pipeline	Process / pipeline
提唱年	19th century (Snow 1854); formalised mid-20th century	1960s (formal codification); widely practiced since mid-20th century
提唱者	Various; foundational work by John Snow (1854) and systematised in modern form by Brian MacMahon and colleagues	Classical epidemiology tradition; systematized by Brian MacMahon and Thomas Pugh (1960s)
種類	Observational epidemiological study	Observational, descriptive/analytic epidemiological design
原典	Morgenstern, H. (1995). Ecologic studies in epidemiology: concepts, principles, and methods. Annual Review of Public Health, 16(1), 61–81.	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
別名	aggregate study, correlational study, ecological correlation study, population-level study	prevalence study, cross-sectional survey, transversal study, cross-sectional design
関連	5	6
概要	An ecological study is an observational epidemiological design in which the unit of analysis is a group or population — a country, region, city, or time period — rather than an individual. Exposures and outcomes are measured as aggregates (rates, proportions, or means) and then correlated across groups to generate or evaluate hypotheses about population-level associations between risk factors and disease.	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.