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': 'Number of new cases occurring in a defined population during a specified period of time is known as: March 2013 \nSelect and explain. \nA. Prevalence, B. Incidence, C. Relative risk, D. Attributable risk', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. B i.e. Incidence Incidence is a measure of the risk of developing some new condition within a specified period of time. Although sometimes loosely expressed simply as the number of new cases during some time period, it is better expressed as a propoion or a rate with a denominator.', 'role': 'assistant'}]