Define specificity in epidemiology?

Specificity in epidemiology refers to the ability of a diagnostic test or screening tool to correctly identify individuals who do not have a particular disease or condition. It measures the proportion of true negatives among all individuals without the disease. In other words, specificity indicates how well a test can accurately rule out the presence of a disease in healthy individuals. A high specificity value indicates a low rate of false positives, meaning that the test is reliable in correctly identifying those who are disease-free.