Table 1.

Operating characteristics for the six scenarios, averaged over simulated trials, for two blocks with patients per block. Each column is a different trial design: AC, FC (0.3), FC (0.5), FC (0.7) are all enrichment trials. These designs do not restrict entry in the first block. ‘A-C’ uses an adaptive cutpoint in the second block with candidate values , ‘F-C()’ uses a fixed cutpoint with value . ‘Non-A’ is a standard unenriched design. ‘Sensitivity’ and ‘Specificity’ are given for detecting the population which benefits. ‘Effect size’ is the true effect size for the designated population. ‘Bias’ is the amount by which each procedure over-estimates that effect size. ‘root-MSE’ is the root-mean-square error of the effect size estimate for the designated population. All operating characteristics, other than power and accrual time, are averaged only over successful trials

		AC	Non-A	FC (0.3)	FC (0.5)	FC (0.7)
1	Power	0.52	0.04	0.35	0.51	0.6
	Sensitivity	0.95	1	0.96	0.95	0.94
	Specificity	0.9	0	0.89	0.9	0.91
	Accrual time	486	300	428	471	515
	Effect size	0.21	0	0.21	0.21	0.21
	Bias	0.04	0.14	0.06	0.05	0.04
	Root-MSE	0.06	0.14	0.08	0.06	0.06
2	Power	0.36	0.35	0.34	0.35	0.36
	Sensitivity	0.9	1	0.91	0.9	0.88
	Specificity	X	X	X	X	X
	Accrual time	372	300	328	366	403
	Effect size	0.09	0.09	0.09	0.09	0.09
	Bias	0.05	0.06	0.05	0.05	0.05
	Root-MSE	0.06	0.07	0.06	0.06	0.06
3	Power	0.84	0.59	0.75	0.82	0.86
	Sensitivity	0.9	1	0.92	0.9	0.89
	Specificity	0.78	0	0.76	0.78	0.79
	Accrual time	380	300	341	371	411
	Effect size	0.19	0.12	0.19	0.19	0.19
	Bias	0.03	0.04	0.04	0.03	0.02
	Root-MSE	0.05	0.05	0.06	0.05	0.05
4	Power	0.22	0.19	0.2	0.23	0.25
	Sensitivity	0.99	1	0.99	1	1
	Specificity	0.24	0	0.18	0.23	0.28
	Accrual time	416	300	362	403	432
	Effect size	0.06	0.05	0.06	0.06	0.07
	Bias	0.08	0.07	0.08	0.08	0.07
	Root-MSE	0.08	0.07	0.09	0.08	0.07
5	Power	0.41	0.29	0.37	0.42	0.46
	Sensitivity	0.99	1	1	0.99	0.99
	Specificity	0.3	0	0.24	0.31	0.34
	Accrual time	413	300	352	398	445
	Effect size	0.1	0.07	0.09	0.1	0.11
	Bias	0.06	0.06	0.07	0.06	0.05
	Root-MSE	0.07	0.07	0.08	0.07	0.06
6	Power	0.51	0.5	0.5	0.48	0.51
	Sensitivity	0.85	1	0.89	0.87	0.83
	Specificity	X	X	X	X	X
	Accrual time	374	300	331	362	402
	Effect size	0.1	0.1	0.1	0.1	0.1
	Bias	0.05	0.04	0.05	0.05	0.05
	Root-MSE	0.06	0.05	0.06	0.06	0.06