手法を比較

	生態学的研究	症例対照研究
分野	疫学	疫学
系統	Process / pipeline	Process / pipeline
提唱年	19th century (Snow 1854); formalised mid-20th century	1950s (formal methodology); precursors in the 1920s
提唱者	Various; foundational work by John Snow (1854) and systematised in modern form by Brian MacMahon and colleagues	Janet Lane-Claypon (early precursors, 1926); formalized by Brian MacMahon and Jerome Cornfield in the 1950s–1960s
種類	Observational epidemiological study	Observational analytic study design
原典	Morgenstern, H. (1995). Ecologic studies in epidemiology: concepts, principles, and methods. Annual Review of Public Health, 16(1), 61–81.	Schlesselman, J.J. (1982). Case-Control Studies: Design, Conduct, Analysis. Oxford University Press. ISBN: 978-0195027860
別名	aggregate study, correlational study, ecological correlation study, population-level study	case-referent study, case-control design, retrospective case-control, case-control analysis
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 case-control study is a retrospective observational design in which individuals who have developed a disease or outcome of interest (cases) are compared with individuals who have not (controls) to determine whether prior exposure to a putative risk factor differs between the two groups. The primary measure of association is the odds ratio, which approximates the relative risk when the outcome is rare. Case-control studies are especially efficient for investigating rare diseases and generating etiological hypotheses.