Table 3 Simulation results for dropping treatment arms based on the first rule (R1) and the absolute bias for such arms in the estimated treatment effect at the time of dropping decision– all priors on pk (k=A,B,C) are non-informative beta(1, 1) priors, when decision threshold is set at 0.95
Sample size | True benefit | Posterior mean estimate biases | Enrolled sample sizes | % Early stopping | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
dB | dC | pA | pB | pC | nA | nB | nC | A | % early B | % early C | |
40 | −0.20 | 0.00 | −0.0051 | 0.0305 | −0.0063 | 36.3504 | 15.0121 | 36.3180 | 15.32 % | 96.09 % | 15.15 % |
−0.15 | 0.00 | −0.0058 | 0.0061 | −0.0057 | 36.2548 | 21.3829 | 36.3305 | 15.43 % | 79.69 % | 15.19 % | |
−0.10 | 0.00 | −0.0063 | −0.0066 | −0.0062 | 36.3540 | 27.9657 | 36.3594 | 15.20 % | 53.98 % | 15.36 % | |
−0.05 | 0.00 | −0.0056 | −0.0076 | −0.0072 | 36.2719 | 33.0725 | 36.2428 | 15.44 % | 30.66 % | 15.86 % | |
0.00 | 0.00 | −0.0050 | −0.0057 | −0.0063 | 36.2726 | 36.4040 | 36.4653 | 15.77 % | 15.11 % | 14.85 % | |
0.05 | 0.00 | −0.0073 | −0.0034 | −0.0049 | 36.2420 | 38.1107 | 36.3738 | 15.75 % | 7.33 % | 15.23 % | |
0.10 | 0.00 | −0.0077 | −0.0011 | −0.0049 | 36.2214 | 39.1845 | 36.3761 | 15.91 % | 2.92 % | 14.88 % | |
0.15 | 0.00 | −0.0044 | −0.0008 | −0.0070 | 36.4279 | 39.6107 | 36.2580 | 14.86 % | 1.35 % | 15.47 % | |
0.20 | 0.00 | −0.0044 | −0.0016 | −0.0060 | 36.3945 | 39.8325 | 36.3640 | 15.06 % | 0.55 % | 15.29 % | |
100 | −0.20 | 0.00 | −0.0206 | 0.0305 | −0.0205 | 84.2873 | 15.4339 | 84.3159 | 22.80 % | 99.99 % | 22.82 % |
−0.15 | 0.00 | −0.0188 | −0.0007 | −0.0203 | 84.7484 | 24.5031 | 84.4050 | 21.95 % | 99.27 % | 22.22 % | |
−0.10 | 0.00 | −0.0202 | −0.0212 | −0.0197 | 84.4487 | 43.6230 | 84.5338 | 22.31 % | 85.84 % | 22.44 % | |
−0.05 | 0.00 | −0.0191 | −0.0276 | −0.0199 | 84.8712 | 66.7741 | 84.3454 | 21.99 % | 52.46 % | 22.57 % | |
0.00 | 0.00 | −0.0216 | −0.0207 | −0.0216 | 84.0536 | 84.2135 | 83.8033 | 22.86 % | 22.67 % | 23.36 % | |
0.05 | 0.00 | −0.0203 | −0.0115 | −0.0196 | 84.6003 | 93.1786 | 84.7271 | 22.28 % | 8.66 % | 22.24 % | |
0.10 | 0.00 | −0.0194 | −0.0050 | −0.0202 | 84.6521 | 97.3946 | 84.1845 | 21.94 % | 3.08 % | 22.76 % | |
0.15 | 0.00 | −0.0194 | −0.0023 | −0.0202 | 84.8085 | 98.9283 | 84.6060 | 22.00 % | 1.20 % | 22.06 % | |
0.20 | 0.00 | −0.0199 | −0.0024 | −0.0215 | 84.5757 | 99.4983 | 84.1044 | 22.02 % | 0.56 % | 22.94 % | |