This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Epidemiology, Subject name: Social & Preventive Medicine
[{'content': 'All of the following are characteristics of case control study except \nSelect and explain. \nA. Quick result are obtained, B. Measures incidence rate, C. Proceeds from effect to cause, D. Inexpensive study', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Disadvantages of case control study Problems of bias relies on memory or past records Selection of an appropriate control group may be difficult Cannot measure incidence and can only estimate relative risk Do not distinguish between cause and associated factors Another major concern representatives of cases and control (refer pgno:74 park 23 rd edition)', 'role': 'assistant'}]