مقایسهٔ روش‌ها

	آزمایش بالینی تصادفی چندمرکزی	مطالعه کوهورت
حوزه	اپیدمیولوژی	اپیدمیولوژی
خانواده	Process / pipeline	Process / pipeline
سال پیدایش	1970s–1980s (widespread adoption for large-scale efficacy trials)	Mid-20th century (formal epidemiological design codified ~1950s)
پدیدآور	Evolved from single-center RCT methodology; consolidated through landmark trials such as the MRC streptomycin trial (1948) and large cardiovascular mega-trials of the 1970s–1980s	Doll & Hill (British Doctors Study, 1951); Snow (cholera, 1854)
نوع	Interventional experimental design	Observational longitudinal study design
منبع بنیادین	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
نام‌های دیگر	multi-site RCT, multicenter RCT, multinational randomized trial, multicenter controlled trial	longitudinal study, follow-up study, panel study, incidence study
مرتبط	6	6
خلاصه	A multicenter randomized clinical trial (RCT) is an experimental study in which eligible participants are randomly assigned to intervention or control arms simultaneously across two or more clinical sites. By combining the rigor of randomization with enrollment from geographically or institutionally diverse centers, this design produces large samples and externally valid effect estimates that single-center trials rarely achieve. It is the regulatory gold standard for confirmatory efficacy and safety evaluation of new treatments.	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.