Table 2. The proportion correctly identified by severity of abnormality as well as the sensitivity, specificity and area under the ROC curve (AUC) for each study design in trials 1 and 2 by classification difficulty.
| Trial 1 | Trial 2 | ||||||||
| Proportion correctly identified | Proportion correctly identified | ||||||||
| 0.03c | 0.05c | 0.03c_500_90% | 0.03c_5000_99% | 0.03c | 0.05c | 0.03c_500_90% | 0.03c_5000_99% | ||
| Mildly abnormal (N = 1200) | 57% | 64% | 55% | 72% | 67% | 69% | 67% | 79% | |
| Normal (N = 600) | 77% | 75% | 87% | 64% | 87% | 86% | 89% | 52% | |
| Severely abnormal (N = 200) | 96% | 92% | 90% | 99% | 99% | 96% | 98% | 99% | |
| Specificity | Specificity | ||||||||
| 0.03c | 0.05c | 0.03c_500_90% | 0.03c_5000_99% | 0.03c | 0.05c | 0.03c_500_90% | 0.03c_5000_99% | ||
| Normal-Mildly abnormal (Difficult classification) | 74% | 68% | 85% | 64% | 87% | 86% | 89% | 52% | |
| Normal- Severely abnormal (Easy classification) | 74% | 68% | 85% | 64% | 87% | 86% | 89% | 52% | |
| Normal-Abnormal (All) | 74% | 68% | 85% | 64% | 87% | 86% | 89% | 52% | |
| Sensitivity | Sensitivity | ||||||||
| 0.03c | 0.05c | 0.03c_500_90% | 0.03c_5000_99% | 0.03c | 0.05c | 0.03c_500_90% | 0.03c_5000_99% | ||
| Normal-Mildly abnormal (Difficult classification) | 61% | 70% | 61% | 72% | 67% | 69% | 67% | 79% | |
| Normal- Severely abnormal (Easy classification) | 98% | 99% | 98% | 99% | 99% | 96% | 98% | 98% | |
| Normal-Abnormal (All) | 66% | 74% | 66% | 76% | 72% | 73% | 72% | 82% | |
| Area under the ROC curve (AUC) | Area under the ROC curve (AUC) | ||||||||
| 0.03c | 0.05c | 0.03c_500_90% | 0.03c_5000_99% | 0.03c | 0.05c | 0.03c_500_90% | 0.03c_5000_99% | ||
| AUC (95%CI): Normal-Mildly abnormal (Difficult classification) | 0.678(0.656–0.700 ) | 0.692(0.669–0.715 ) | 0.731(0.711–0.751 ) | 0.681(0.658–0.704 ) | 0.771(0.752–0.790) | 0.777(0.758–0.796) | 0.784(0.766–0.802) | 0.656(0.634–0.680) | |
| AUC (95%CI): Normal-Severely abnormal (Easy classification) | 0.871(0.850–0.889) | 0.833(0.813–0.854 ) | 0.915(0.895–0.930) | 0.819(0.799–0.839 ) | 0.929(0.913–0.944) | 0.91(0.891–0.929) | 0.938(0.922–0.953) | 0.754(0.732–0.776) | |
| AUC (95%CI): Normal-Abnormal (All) | 0.704(0.683–0.724) | 0.712(0.692–0.732) | 0.757(0.738–0.776) | 0.701(0.680–0.721) | 0.794(0.776–0.811) | 0.796(0.778–0.814) | 0.806(0.789–0.823) | 0.671(0.648–0.693) | |
(0.03c = study design 1; 0.05c = study design 2; 0.03c_500_90% = study design 3; 0.03c_5000_99% = study design 4).