This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Analytical Epidemiology, Subject name: Social & Preventive Medicine
Best epidemiological study is - 
Select and explain. 
A. RCT, B. Meta-analysis, C. Cohort study, D. Case-control study
B: Meta-analysis
Answer: B: Meta-analysis 
Explanation: Ans, is 'b' i.e., Meta-analysis o Here are the different epidemiological studies with decreasing order of accuracy to test the association between risk factor and diseaseSystematic review and meta-analysis - Overall most reliableRandomized controlled trials (controlled clinical trails) - Most reliable individual study.Retrospective (Non-concurrent''historic) Cohort study.Prospective (concurrent) Cohort study.Case control studyCross-sectional studyEcological study