Specificity refers to

• A. The ability to identify true positives
• B. The rate of false positives
• C. How well a test identifies only those members of the defined group
• D. The overall difficulty of the test

Answer: (C)

Specificity is about correctly labeling people who do not have the condition. It’s the proportion of true negatives among everyone without the disease. A high specificity means few healthy people are falsely identified as positive, so when the test is positive, it’s strong evidence the person actually has the condition (it helps rule in). The false positive rate (1 minus specificity) is related but not the same as specificity itself. The other options describe different ideas—true positives (sensitivity) or overall test difficulty—not what specificity measures.