Intraobserver and interobserver variability statistics
| Intraobserver | Interobserver | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Mean difference between measures | SD of difference | Range of CDR | 95% TC (% of range) | ICC | CV | ⩾0.2 CDR difference | Mean difference between measures | SD of difference | Range of CDR | 95% TC (% of range) | ICC | CV | ⩾0.2 CDR difference | ||
| V-CDR | 0.009 | 0.069 | 0.08–0.95 | 15.6% | 0.919 | 11.7% | 2% | -0.018 | 0.072 | 0.12–1.00 | 15.9% | 0.898 | 11.8% | 3% | |
| H-CDR | 0.000 | 0.056 | 0.2– 0.92 | 15.3% | 0.941 | 9.5% | 0% | 0.002 | 0.071 | 0.18–0.91 | 19.2% | 0.889 | 12.1% | 2% | |
| A-CDR | 0.001 | 0.053 | 0.06–0.84 | 13.4% | 0.955 | 14.2% | NA | -0.01 | 0.068 | 0.06–0.89 | 16.2% | 0.921 | 17.9% | NA | |
| P-CDR | 0.002 | 0.047 | 0.27–0.94 | 13.6% | 0.946 | 7.6% | NA | -0.007 | 0.06 | 0.27–0.95 | 17.2% | 0.904 | 9.7% | NA | |
TC = tolerance for change; V-CDR = vertical cup-disc ratio; H-CDR = horizontal cup-disc ratio; A-CDR = area cup-disc ratio; P-CDR = perimeter cup-disc ratio; ICC = intraclass correlation coefficient; CV = coefficient of variation.