This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Social & Preventive Medicine
[{'content': 'Most impoant factor which decides the results of a randomized controlled trial is: March 2005 \nSelect and explain. \nA. Inclusion of all age groups, B. 50% treated with placebo and 50% with drugs, C. 100% follow up, D. Effective randomization', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. D: Effective randomization It is a procedure by which the paicipants are allocated into groups usually called 'study' and 'control' groups. Randomization is the hea of control trials. It eliminates selection bias", 'role': 'assistant'}]