II. Definitions
- Receiver Operating Characteristic (ROC)
- Graphical representation of balance between Test Sensitivity and Test Specificity
- Test Criterion
- Threshold for which a test is considered positive
- A Screening Test may set the test criterion low to minimize False Negatives (at the expense of increased False Positives)
- A confirmatory test may set the test criterion high to minimize False Positives (at the expense of increased False Negatives)
III. Technique
- Given a range of test criteria (from low threshold to high threshold)
- Identify the Test Sensitivity and Test Specificity at each of the test criteria
- For each test criteria, plot the Test Sensitivity and 1-Test Specificity
- True Positive Rate (Test Sensitivity)
- Plot on Y axis
- False Positive Rate (1-Test Specificity)
- Plot on X axis
- True Positive Rate (Test Sensitivity)
IV. Interpretation
- Identify the Shoulder or inflection point in the curve as the optimal threshold
- Best tests have maximal area under the curve (AUC)
- Most distinct, highest inflection point best distinguishes between positive and negative test
- Poor tests, have no inflection point
- Flat, linear relationship between Test Sensitivity and 1-Test Specificity at various test criteria
V. Resources
- Receiver Operating Characteristic (Wikipedia)
VI. References
- Desai (2014) Clinical Decision Making, AMIA’s CIBRC Online Course