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': 'Which one of the following will be affected by inter- observer variation in epidemiological studies \nSelect and explain. \nA. Sensitivity, B. Predictive value of the positive test, C. Specificity, D. Reliability', 'role': 'user'}, {'content': 'Answer: A \nExplanation: the term sensitivity was introduced by Yerushalmy in 1940 s as a statistical index of diagnostic accuracy.it has been defined as the ability of a test to identify correctly all those who have the disease that is true positive.it also gets affected by the intern observer variations in the epidemiological studies. ref:park&;s textbook of preventive and social medicine,22 nd edition,pg no 131 .', 'role': 'assistant'}]