Table 1.

FWER, sample size, critical value (CV) and overall power comparisons for 90% marginal power

Design	FWER	Total sample size	CV	Overall power
Two separate trials	0.0494	936	1.96	0.81
Two separate trials: adjustment for multiplicity	0.0250	1104	2.24	0.81
Single trial: no multiplicity adjustment	0.0454	702	1.96	0.83
Single trial: Dunnett adjustment for multiplicity	0.0250	816	2.21	0.83
Adding an arm: no multiplicity adjustment	0.0477	802	1.96	0.82
Adding an arm: Dunnett adjustment for multiplicity	0.0250	922	2.23	0.82