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
In a case control study, the most characterstic feature is - 
Select and explain. 
A. Odds ratio estimation, B. Problem bias, C. Yield incidence rate, D. Expensive
A: Odds ratio estimation
Answer: A: Odds ratio estimation 
Explanation: Odds ratio is a measure of the strength of association between risk factor and outcome (refer pgno:73 park 23 rd edition)