قارن الطرق

	التجربة السريرية العشوائية (RCT)	الدراسة الوبائية المقطعية
المجال	علم الأوبئة	علم الأوبئة
العائلة	Process / pipeline	Process / pipeline
سنة النشأة	1948 (first rigorously conducted RCT — MRC streptomycin trial)	1960s (formal codification); widely practiced since mid-20th century
صاحب الطريقة	Austin Bradford Hill; MRC Streptomycin Trial team	Classical epidemiology tradition; systematized by Brian MacMahon and Thomas Pugh (1960s)
النوع	Interventional experimental study	Observational, descriptive/analytic epidemiological design
المصدر التأسيسي	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	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
الأسماء البديلة	RCT, randomized controlled trial, randomised controlled trial, clinical randomized trial	prevalence study, cross-sectional survey, transversal study, cross-sectional design
ذات صلة	6	6
الملخص	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 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.