Asymptotically optimal response-adaptive designs for allocating the best treatment: an overview

Response-adaptive designs are being used increasingly in applications, and this is especially so in early phase clinical trials. This paper reviews a particular class of response-adaptive designs that have the property of picking the superior treatment with probability tending to one. This is a desirable property froman ethical point of view in clinical trials. The model underlying such designs is a randomly reinforced urn. This paper provides an overview of results for these designs, starting from the early paper of Durham and Yu (1990) until the recent work by Flournoy, May, Moler and Plo (2010)