手法を比較

	ランダム化比較試験 (RCT)	コホート研究
分野	疫学	疫学
系統	Process / pipeline	Process / pipeline
提唱年	1948 (first rigorously conducted RCT — MRC streptomycin trial)	Mid-20th century (formal epidemiological design codified ~1950s)
提唱者	Austin Bradford Hill; MRC Streptomycin Trial team	Doll & Hill (British Doctors Study, 1951); Snow (cholera, 1854)
種類	Interventional experimental study	Observational longitudinal study design
原典	Friedman, L. M., Furberg, C. D., DeMets, D. L., Reboussin, D. M., & Granger, C. B. (2015). Fundamentals of Clinical Trials (5th ed.). Springer. ISBN: 978-3319185385	Rothman, K. J., Greenland, S., & Lash, T. L. (2008). Modern Epidemiology (3rd ed.). Lippincott Williams & Wilkins. ISBN: 978-0781755641
別名	RCT, randomized controlled trial, randomised controlled trial, clinical randomized trial	longitudinal study, follow-up study, panel study, incidence study
関連	6	6
概要	A randomized clinical trial (RCT) is an experimental study design in which participants are randomly assigned to an intervention group or a control group, then followed prospectively to compare outcomes. Random allocation is the defining feature: it distributes known and unknown confounders across groups by chance, making the RCT the strongest individual study design for establishing causal efficacy of a treatment or intervention under controlled conditions.	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.