Table 3. The accuracy of baseline centiles to identify first-born twins with high myopia (SE ≤-6.0D) at the age of 15 years by sex.
| Baseline centile (%) | True positive (n) | False positive (n) | False negative (n) | True negative (n) | Total (n) | Sensitivity(%) | Specificity(%) | Positive predictive value (%) | Negative predictive value (%) | MCC |
|---|---|---|---|---|---|---|---|---|---|---|
| Boys | ||||||||||
| 3rd | 3 | 0 | 4 | 163 | 170 | 0.43 | 1.00 | 1.00 | 0.98 | 0.6 |
| 5th | 6 | 0 | 1 | 163 | 170 | 0.86 | 1.00 | 1.00 | 0.99 | 0.9 |
| 10th | 7 | 9 | 0 | 154 | 170 | 1.00 | 0.94 | 0.44 | 1.00 | 0.6 |
| 25th | 7 | 42 | 0 | 121 | 170 | 1.00 | 0.74 | 0.14 | 1.00 | 0.3 |
| Girls | ||||||||||
| 3rd | 4 | 1 | 3 | 176 | 184 | 0.57 | 0.99 | 0.80 | 0.98 | 0.7 |
| 5th | 7 | 7 | 0 | 170 | 184 | 1.00 | 0.96 | 0.50 | 1.00 | 0.7 |
| 10th | 7 | 28 | 0 | 149 | 184 | 1.00 | 0.84 | 0.20 | 1.00 | 0.4 |
| 25th | 7 | 67 | 0 | 110 | 184 | 1.00 | 0.62 | 0.09 | 1.00 | 0.2 |
MCC: Mathews correlation coefficient