ABSTRACT

Response-adaptive randomization or allocation is a randomization tech-

nique in which the allocation of patients to treatment groups is based on

the responses (outcomes) of the previous patients. The main purpose is to

provide a better chance of randomizing the patients to a superior treatment

group based on the knowledge about the treatment effect at the time of

randomization. As a result, response-adaptive randomization takes ethical

concerns into consideration. The well-known response-adaptive models in-

clude the play-the-winner (PW) model and the randomized play-the-winner

(RPW) model.