If a cognitive screening tool has high specificity, what does this psychometric property guarantee?

• A. The test accurately catches everyone who genuinely has cognitive decline
• B. The test yields highly stable scores when administered by different clinicians
• C. The test is highly sensitive to the earliest structural changes in the cortex
• D. The test correctly identifies individuals who do not have cognitive decline

Answer: (D)

Specificity tells you how often the test correctly labels people without cognitive decline as negative. When this property is high, almost every healthy person will receive a negative result, meaning there are very few false positives. So a negative result in someone who truly does not have cognitive decline is highly trustworthy, which is why the statement about correctly identifying individuals who do not have cognitive decline fits best. This doesn’t guarantee catching all cases (that’s about sensitivity), nor does it speak to consistency across clinicians or to early structural changes—those are separate psychometric aspects. For example, with high specificity, among 100 healthy individuals, only a small number would be misclassified as positive, while the majority are correctly identified as negative.