Table 3 Empirical power and percentage of trials switching to the quota sampling scheme for the modified quota sampling method
θ | Planned distribution of the prognostic factor | Planned n t | Empirical power | Percent of trials switching to quota sampling |
|---|---|---|---|---|
Misspecification of the prognostic factor: -5% | ||||
5 | 10% | 1,418 | 0.8012 | 99.98% |
20% | 798 | 0.7736 | 74.08% | |
30% | 608 | 0.7802 | 47.52% | |
40% | 532 | 0.7932 | 36.64% | |
50% | 512 | 0.8060 | 35.50% | |
15 | 10% | 178 | 0.6636 | 33.04% |
20% | 100 | 0.7400 | 11.06% | |
30% | 78 | 0.7940 | 11.84% | |
40% | 68 | 0.8164 | 11.90% | |
50% | 64 | 0.8122 | 8.48% | |
Misspecification of the prognostic factor: -15% | ||||
5 | 10% | 1,418 | -- | -- |
20% | 798 | 0.8022 | 100.00% | |
30% | 608 | 0.8024 | 100.00% | |
40% | 532 | 0.8058 | 99.94% | |
50% | 512 | 0.8090 | 99.82% | |
15 | 10% | 178 | -- | -- |
20% | 100 | 0.7788 | 89.06% | |
30% | 78 | 0.7834 | 63.64% | |
40% | 68 | 0.7904 | 49.70% | |
50% | 64 | 0.8038 | 40.00% | |
Misspecification of the prognostic factor: +5% | ||||
5 | 10% | 1,418 | 0.8000 | 98.28% |
20% | 798 | 0.8090 | 67.72% | |
30% | 608 | 0.8278 | 49.32% | |
40% | 532 | 0.8092 | 37.08% | |
50% | 512 | 0.7984 | 36.30% | |
15 | 10% | 178 | 0.8880 | 35.14% |
20% | 100 | 0.8656 | 16.62% | |
30% | 78 | 0.8542 | 10.94% | |
40% | 68 | 0.8350 | 7.86% | |
50% | 64 | 0.8198 | 8.60% | |
Misspecification of the prognostic factor: +15% | ||||
5 | 10% | 1,418 | 0.8738 | 100.00% |
20% | 798 | 0.8010 | 100.00% | |
30% | 608 | 0.8092 | 99.98% | |
40% | 532 | 0.8088 | 99.80% | |
50% | 512 | 0.8064 | 99.86% | |
15 | 10% | 178 | 0.8942 | 97.82% |
20% | 100 | 0.8504 | 72.44% | |
30% | 78 | 0.8572 | 50.72% | |
40% | 68 | 0.8466 | 38.48% | |
50% | 64 | 0.8174 | 40.88% | |