Define specificity.

Define specificity.

• A. The probability that a person does not have the condition given a negative test result
• B. An expression of test accuracy in correctly identifying the presence of a problem as established by a gold standard test
• C. An expression of test accuracy in correctly identifying the absence of a problem as established by a gold standard test
• D. The rate of false negatives

Answer: (C)

Specificity is the true negative rate: among people who do not have the condition, the test correctly gives a negative result. It is defined in relation to a gold standard, measuring how well the test avoids false positives in those without disease. The description that the test correctly identifying the absence of a problem as established by a gold standard matches this idea. Other metrics describe different aspects: sensitivity concerns correctly identifying those with the condition, negative predictive value looks at the probability of being disease-free given a negative result, and the rate of false negatives refers to missed detections among those who actually have the condition.

Specificity is the true negative rate: among people who do not have the condition, the test correctly gives a negative result. It is defined in relation to a gold standard, measuring how well the test avoids false positives in those without disease. The description that the test correctly identifying the absence of a problem as established by a gold standard matches this idea. Other metrics describe different aspects: sensitivity concerns correctly identifying those with the condition, negative predictive value looks at the probability of being disease-free given a negative result, and the rate of false negatives refers to missed detections among those who actually have the condition.