Abstract: RPW rule is a most commonly used randomization method of adaptive design. In this article, the influence of three parameters of RPW(u,a,b) rule on the treatment allocation proportion by means of Monte Carlo simulation were explored. The results indicated that the difference of allocation proportions between two treatment groups decreases with the increase of u value and trend towards zero when u become very large. However parameter a has an inverse influence of that of u. Compared with parameter a and u, the influence of parameter b is more complex, the difference of allocation proportions between two treatment groups increases as b increases, but the extent of this influence is too low to be concerned. In addition, the treatment allocation proportions were investigated through computer simulation experiment under different situations of treatment successful probabilities. We hope this study can provide some references for the application of RPW rule in practical clinical trials.

Key words: Adaptive design, Randomized play the winner rule, Simulation examination