Table 3.

Proportion of group-sequential trials with subjects numbers superior to fixed designs NSN (p_C = 0.50)

		∆ = 0.2	∆ = 0.1	∆ = 0	∆ = − 0.1
Standard	S1	0.07	0.13	0.02	0.0004
	S2	0.09	0.15	0.02	0.0003
Changing with time	S1	0.02	0.13	0.04	0.001
	S2	0.1	0.23	0.03	0.0005

Abbreviations: p_C indicates control survival rate; ∆: simulated survival rate difference; F1: fixed single-arm design; S1: group-sequential single-arm design; F2: fixed two-arm design; S2: group-sequential two-arm design; “Standard”: specific case with a fixed control survival rate; “Changing with time”: specific case with an increase of the control survival rate over time