Merck Sharp & Dohme Corp., 126 East Lincoln Avenue, Rahway, NJ 07065-0900, USA.
Stat Med. 2011 Apr 15;30(8):812-24. doi: 10.1002/sim.4167. Epub 2011 Jan 13.
Studies with unequal allocation to two or more treatment groups often require a large block size for permuted block allocation. This could present a problem in small studies, multi-center studies, or adaptive design dose-finding studies. In this paper, an allocation procedure, which generalizes the maximal procedure by Berger, Ivanova, and Knoll to the case of K≥2 treatment groups and any allocation ratio, is offered. Brick tunnel (BT) randomization requires the allocation path drawn in the k-dimensional space to stay close to the allocation ray that corresponds to the targeted allocation ratio. Specifically, it requires the allocation path to be confined to the set of the k-dimensional unitary cubes that are pierced by the allocation ray (the 'brick tunnel'). The important property of the BT randomization is that the transition probabilities at each node within the tunnel are defined in such a way that the unconditional allocation ratio is the same for every allocation step. This property is not necessarily met by other allocation procedures that implement unequal allocation.
研究中经常需要将两个或多个治疗组分配到不等的组中，这通常需要较大的区组大小进行随机区组分配。在小型研究、多中心研究或适应性设计剂量发现研究中，这可能会成为一个问题。在本文中，提供了一种分配程序，该程序将 Berger、Ivanova 和 Knoll 的最大程序推广到 K≥2 个治疗组和任何分配比例的情况。砖隧道（BT）随机化要求在 k 维空间中绘制的分配路径靠近对应目标分配比例的分配射线。具体来说，它要求分配路径被限制在分配射线穿过的 k 维单位立方体集合内（“砖隧道”）。BT 随机化的重要性质是，隧道内每个节点的转移概率的定义方式使得无条件分配比例在每个分配步骤中都是相同的。其他实施不等分配的分配程序不一定具有此性质。
