Recall, also called test sensitivity, measures how often a medical test returns positive when the tested condition is present. A test with 99.5% sensitivity detects 995 of 1,000 genuine cases. section 13.4
Sensitivity describes positive-case accuracy, not the probability that a positive result means the condition is present. That interpretation also depends on the prior probability and the test’s specificity. section 13.4
A highly sensitive test can still mislead
For Frob Syndrome, the prior is 1 case in 30,000. With 99.5% sensitivity and specificity, 199 genuinely affected people test positive, but 29,999 unaffected people also test positive. Among positive results, the posterior odds are 199 to 29,999, or about 0.7%. section 13.4























