Table 4 Empirical type I error 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 type I error | Percent of trials switching to quota sampling |
|---|---|---|---|---|
Misspecification of the prognostic factor: -5% | ||||
0 | 10% | 1,418 | 0.0528 | 99.90% |
20% | 798 | 0.0506 | 74.26% | |
30% | 608 | 0.0498 | 47.34% | |
40% | 532 | 0.0480 | 36.66% | |
50% | 512 | 0.0492 | 36.06% | |
0 | 10% | 178 | 0.0566 | 34.74% |
20% | 100 | 0.0496 | 12.12% | |
30% | 78 | 0.0528 | 11.24% | |
40% | 68 | 0.0452 | 11.30% | |
50% | 64 | 0.0522 | 8.80% | |
Misspecification of the prognostic factor: -15% | ||||
0 | 10% | 1,418 | -- | -- |
20% | 798 | 0.0500 | 100.00% | |
30% | 608 | 0.0496 | 100.00% | |
40% | 532 | 0.0518 | 99.92% | |
50% | 512 | 0.0568 | 99.76% | |
0 | 10% | 178 | -- | -- |
20% | 100 | 0.0578 | 89.60% | |
30% | 78 | 0.0522 | 62.82% | |
40% | 68 | 0.0542 | 50.56% | |
50% | 64 | 0.0478 | 41.20% | |
Misspecification of the prognostic factor: +5% | ||||
0 | 10% | 1,418 | 0.0568 | 98.68% |
20% | 798 | 0.0490 | 68.74% | |
30% | 608 | 0.0490 | 48.10% | |
40% | 532 | 0.0508 | 36.48% | |
50% | 512 | 0.0508 | 36.64% | |
0 | 10% | 178 | 0.0504 | 34.46% |
20% | 100 | 0.0534 | 16.32% | |
30% | 78 | 0.0496 | 10.90% | |
40% | 68 | 0.0450 | 8.50% | |
50% | 64 | 0.0502 | 8.94% | |
Misspecification of the prognostic factor: +15% | ||||
0 | 10% | 1,418 | 0.0462 | 100.00% |
20% | 798 | 0.0490 | 100.00% | |
30% | 608 | 0.0484 | 100.00% | |
40% | 532 | 0.0516 | 99.76% | |
50% | 512 | 0.0522 | 99.86% | |
0 | 10% | 178 | 0.0452 | 97.48% |
20% | 100 | 0.0444 | 70.72% | |
30% | 78 | 0.0526 | 51.00% | |
40% | 68 | 0.0524 | 38.60% | |
50% | 64 | 0.0528 | 40.72% | |