Table 2.

Allocation ratios, overall power and sample size comparisons for the adding a treatment arm design using optimal allocation when treatments finish recruitment at different times

Stage 3 ratio	Stage 2 ratio	n23	Correlation	Overall power
1:0.2	2.015:1:1	100	0.170	0.852
1:0.3	1.932:1:1	93	0.176	0.850
1:0.4	1.856:1:1	85	0.181	0.848
1:0.5	1.791:1:1	78	0.186	0.847
1:0.6	1.730:1:1	71	0.191	0.845
1:0.7	1.678:1:1	64	0.197	0.844
1:0.8	1.632:1:1	58	0.202	0.843

The total sample size of the trial is based on an adding a treatment arm with 1:1:1 allocation design with a marginal power of 90% and an FWER of 2.5%