Specificity

The ratio of true negatives assessments based on the number of negative assessments, i.e., if four of five negative assessments were properly negative then it has a 0.8 or 80 percent specificity. This shows how effective a test is at providing a correct negative call, i.e., drug not present. If a drug test has low specificity, then it incorrectly indicates people without drugs as having them in their system.