Table 5.
Average sample size and empirical probability of rejecting the null hypothesis, design with interim futility monitoring: Unequal subgroup accrual rates (30%, 20%, 20%, 20%,10%) (10,000 replications)
| Design | True response rate in each subgroup | |||||
|---|---|---|---|---|---|---|
| Case 1 | .1 | .1 | .1 | .1 | .1 | |
| Subgroup-specific analyses | Average sample size | 19.5 | 19.5 | 19.5 | 19.4 | 19.6 |
| Rejection probability | .095 | .090 | .093 | .097 | .098 | |
| HB* Model 1 moderate borrowing | Average sample size | 20.7 | 19.8 | 19.6 | 19.7 | 21.2 |
| Rejection probability | .094 | .091 | .093 | .100 | .096 | |
| HB Model 1 strong borrowing | Average sample size | 20.0 | 19.2 | 19.2 | 19.0 | 20.4 |
| Rejection probability | .026 | .025 | .024 | .027 | .022 | |
| Simple borrowing (LeBlanc et al) | Average sample size | 18.3 | 16.6 | 16.6 | 16.5 | 13.2 |
| Rejection probability | .077 | .070 | .069 | .072 | .055 | |
| Case 2 | .1 | .1 | .1 | .1 | .3 | |
| Subgroup-specific analyses | Average sample size | 19.5 | 19.4 | 19.5 | 19.5 | 24.6 |
| Rejection probability | .093 | .085 | .097 | .094 | .900 | |
| HB Model 1 moderate borrowing | Average sample size | 20.8 | 20.2 | 20.2 | 20.1 | 24.7 |
| Rejection probability | .096 | .087 | .097 | .095 | .898 | |
| HB Model 1 strong borrowing | Average sample size | 20.8 | 20.3 | 20.3 | 20.0 | 24.2 |
| Rejection probability | .033 | .037 | .033 | .037 | .742 | |
| Simple borrowing (LeBlanc et al) | Average sample size | 18.9 | 18.0 | 18.1 | 18.1 | 19.6 |
| Rejection probability | .088 | .077 | .087 | .086 | .645 | |
| Case 3 | .1 | .1 | .1 | .3 | .3 | |
| Subgroup-specific analyses | Average sample size | 19.4 | 19.5 | 19.5 | 24.6 | 24.6 |
| Rejection probability | .093 | .097 | .097 | .893 | .897 | |
| HB Model 1 moderate borrowing | Average sample size | 21.0 | 20.5 | 20.5 | 24.5 | 24.7 |
| Rejection probability | .096 | .098 | .099 | .891 | .897 | |
| HB Model 1 strong borrowing | Average sample size | 21.9 | 21.8 | 21.8 | 24.5 | 24.7 |
| Rejection probability | .051 | .057 | .062 | .800 | .796 | |
| Simple borrowing (LeBlanc et al) | Average sample size | 19.3 | 19.2 | 19.1 | 24.0 | 23.6 |
| Rejection probability | .093 | .096 | .096 | .857 | .848 | |
| Case 4 | .1 | .1 | .3 | .3 | .3 | |
| Subgroup-specific analyses | Average sample size | 19.6 | 19.5 | 24.7 | 24.6 | 24.6 |
| Rejection probability | .095 | .099 | .898 | .899 | .901 | |
| HB Model 1 moderate borrowing | Average sample size | 21.3 | 21.0 | 24.7 | 24.6 | 24.7 |
| Rejection probability | .099 | .102 | .898 | .898 | .903 | |
| HB Model 1 strong borrowing | Average sample size | 23.1 | 23.2 | 24.8 | 24.8 | 24.8 |
| Rejection probability | .085 | .085 | .842 | .845 | .840 | |
| Simple borrowing (LeBlanc et al) | Average sample size | 19.6 | 19.4 | 24.5 | 24.5 | 24.5 |
| Rejection probability | .096 | .099 | .891 | .892 | .892 | |
*
HB = hierarchical Bayesian