What Role Does Prior Probability Play in Screening and Diagnostic Tests?
Prior probability is crucial in interpreting the results of screening and diagnostic tests. It affects the positive predictive value (PPV) and negative predictive value (NPV) of a test. For instance, in a population with a low prior probability of a disease, even a highly specific and sensitive test might yield a lower PPV, leading to a higher chance of false positives. Conversely, in a high prior probability scenario, the same test would have a higher PPV, making it more reliable.
