Diagnostic performance

Diagnostic performance evaluates the ability of a qualitative or quantitative test to discriminate between two subclasses of subjects.

• Measures of diagnostic accuracy
  Diagnostic accuracy measures the ability of a test to detect a condition when it is present and detect the absence of a condition when it is absent.
• ROC plot
  ROC (receiver operating characteristic) curves show the ability of a quantitative diagnostic test to classify subjects correctly as the decision threshold is varied.
• Area under the curve (AUC)
  The area under (a ROC) curve is a measure of the accuracy of a quantitative diagnostic test.
• Difference between the areas under two curves
  The difference between areas under the ROC curves compares the accuracy of two or more diagnostic tests.
• Decision thresholds
  A decision threshold is a value that dichotomizes the result of a quantitative test to a simple binary decision.
• Decision plot
  A decision plot shows a measure of performance (such as sensitivity, specificity, likelihood ratios, or predictive values) against all decision thresholds to help identify optimal decision threshold.