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': 'When an intervention is applied to community to evaluate its usefulness, it is termed as a trial for - \nSelect and explain. \nA. Efficacy, B. Effectiveness, C. Efficiency, D. Effect modification', 'role': 'user'}, {'content': "Answer: B \nExplanation: EVALUATION OF HEALTH SERVICES:\n\nEfficacy: Is the effect or usefulness of an agent/ drug/ vaccine under ideal ‘controlled laboratory’ conditions\nEffectiveness: Is the effect or usefulness of an agent/ drug/ vaccine in real life community situations\nEfficiency: Is the measure of relationship between the results achieved and the effort expended in terms of money,\xa0resources and time\n\n– Efficiency: Output/ Input\n– Evaluation of efficiency:\n1. Cost-benefit analysis: Both input as well as output is in monetary terms\n2. Cost-effectiveness analysis: Input is in monetary terms whereas output is in terms of ‘no. of lives saved'.", 'role': 'assistant'}]