Appendix 2.
Diagnostic accuracy of using plain radiographs to identify elbow fracture patterns - Statistical Analysis
| Elbow fracture pattern | Pattern X | Not Pattern X | |
|---|---|---|---|
| Reference standard | |||
| Correct | True positive (TP) | False negative (FN) | TP + FN |
| Other pattern | False positive (FP) | True negative (TN) | FP + TN |
| Totals | TP + FP | FN + TN | 3869 |
| Diagnostic performance characteristics | |||
| Sensitivity** | TP/ TP + FN | ||
| Specificity† | TN/FP + TN | ||
| Accuracy‡ | TP + TN/TOTAL | ||
| Positive predictive value § | TP/ TP + FP | ||
| Negative predictive value # | TN/FN + TN | ||
**Proportion of patients with an elbow fracture pattern X classified as pattern X (true positives); †proportion of patients with no elbow fracture pattern X fracture dislocation classified as not having pattern X (true negatives); ‡proportion of patients who are correctly classified by the test. Proportion of true positive and true negatives; §probability that a patient with a positive plain radiograph for elbow fracture pattern X has pattern X; #probability that a patient with negative plain radiographs does not have pattern X.