Table 2.

Empirical global power, power for each endpoint and proportion of terminating the trial early assuming equal allocation of type I error rate of 0.025 for each endpoint and using O’Brien-Fleming boundaries; results based on 10,000 simulations

Type of Copula	τ	Empirical Global Power	PFS			OS
			1st Interim	Final Analysis	Power	1st Interim	Final Analysis	Power
Independence	0	0.979	0.206	0.647	0.853	0.221	0.855	0.856
Normal	0.10	0.969	0.205	0.645	0.851	0.211	0.849	0.849
	0.30	0.955	0.202	0.646	0.848	0.217	0.852	0.853
	0.50	0.934	0.209	0.639	0.849	0.216	0.860	0.860
	0.70	0.912	0.203	0.644	0.847	0.209	0.855	0.856
Frank	0.10	0.974	0.203	0.646	0.850	0.206	0.856	0.857
	0.30	0.957	0.207	0.645	0.852	0.215	0.856	0.857
	0.50	0.938	0.203	0.647	0.850	0.218	0.852	0.853
	0.70	0.912	0.204	0.640	0.844	0.215	0.854	0.855
Gumbel	0.10	0.969	0.209	0.638	0.846	0.221	0.853	0.854
	0.30	0.947	0.208	0.638	0.846	0.217	0.854	0.854
	0.50	0.929	0.208	0.639	0.847	0.210	0.857	0.857
	0.70	0.909	0.212	0.638	0.850	0.216	0.854	0.855