Table 1 Empirical power for all three methods when there was no misspecification of the distribution of the prognostic factor
θ | Planned distribution of the prognostic factor | Planned n t | Quota sampling | Modified quota sampling | Sample size re-estimation using conditional power |
|---|---|---|---|---|---|
5 | 10% | 1,418 | 0.8088 | 0.8054 | 0.8836 |
20% | 798 | 0.8152 | 0.8082 | 0.8916 | |
30% | 608 | 0.8178 | 0.8014 | 0.8870 | |
40% | 532 | 0.8116 | 0.8036 | 0.8866 | |
50% | 512 | 0.8156 | 0.8098 | 0.8974 | |
15 | 10% | 178 | 0.8556 | 0.8204 | 0.8890 |
20% | 100 | 0.8490 | 0.8128 | 0.8930 | |
30% | 78 | 0.8442 | 0.8316 | 0.9012 | |
40% | 68 | 0.8556 | 0.8322 | 0.9038 | |
50% | 64 | 0.8412 | 0.8256 | 0.9082 |