手法を比較

	前向き生態学的研究	コホート研究
分野	疫学	疫学
系統	Process / pipeline	Process / pipeline
提唱年	1950s–1970s (ecological epidemiology); prospective variant widely applied from 1980s onward	Mid-20th century (formal epidemiological design codified ~1950s)
提唱者	Ecological study design formalised in epidemiology mid-20th century; prospective variant established through environmental and chronic disease research	Doll & Hill (British Doctors Study, 1951); Snow (cholera, 1854)
種類	Observational epidemiological study design	Observational longitudinal study design
原典	Morgenstern, H. (1998). Ecological studies. In K. J. Rothman & S. Greenland (Eds.), Modern Epidemiology (2nd ed., pp. 459–480). Lippincott-Raven.	Rothman, K. J., Greenland, S., & Lash, T. L. (2008). Modern Epidemiology (3rd ed.). Lippincott Williams & Wilkins. ISBN: 978-0781755641
別名	prospective ecologic study, prospective aggregate-level study, prospective group-level study, ecological cohort study	longitudinal study, follow-up study, panel study, incidence study
関連	4	6
概要	A prospective ecological study is an observational epidemiological design in which groups — not individuals — serve as the unit of analysis, and exposure data are collected going forward in time before outcomes are measured. Investigators define geographically, politically, or socially bounded populations, characterise their aggregate exposures at baseline, then ascertain group-level outcomes (disease rates, mortality rates) at one or more later time points. Because exposure precedes outcome measurement, this design provides stronger temporal evidence than retrospective ecological studies.	A cohort study assembles a group of individuals who share a common starting point — typically freedom from the outcome of interest — and follows them over time to observe who develops the outcome. By comparing incidence rates between exposed and unexposed subgroups, researchers can estimate relative risk and absolute risk differences. Cohort studies are the gold-standard observational design for measuring disease incidence and establishing temporal relationships between exposure and outcome.