This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Screening, Subject name: Social & Preventive Medicine
[{'content': 'Diagnostic power of the test is reflected by- \nSelect and explain. \nA. Sensitivity, B. Specificity, C. Reliability, D. Predictivity', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ref:Parks 25th edition pg 153 Predictive value reflects the diagnostic power of a test. Positive predictive value indicates the probability that a patient with a positive test result has, in fact, the disease in question. The more prevalent disease in a given population, the more accurate will be the predictive value of a positive screening test. As prevalence decrease, positive predictive value decreases.', 'role': 'assistant'}]