Department of Statistics, London School of Economics, London WC2A 2AE, UK.
Stat Med. 2012 Dec 10;31(28):3494-503. doi: 10.1002/sim.5416. Epub 2012 Jun 27.
The paper assesses biased-coin designs for sequential treatment allocation in clinical trials. Comparisons emphasise the importance of considering randomness, as well as treatment balance, which are calculated as bias and loss. In the numerical examples, the responses are assumed normally distributed, perhaps after transformation, and balance is required over a set of covariates. The effect of covariate distribution on the properties of five allocation rules is investigated, with an emphasis on methods of comparison, which also apply to other forms of response. The concept of admissibility shows that the widely used minimisation rule is outperformed by Atkinson's rule derived from the theory of optimum experimental design. We present a simplified form of this rule. For this rule, the ability to guess the next treatment allocation decreases with study size. For the other rules, it is constant.
本文评估了临床试验中序贯治疗分配的偏币设计。比较强调了考虑随机性以及治疗平衡的重要性，这可以通过偏差和损失来计算。在数值示例中，假设响应正态分布，可能经过转换，并且需要在一组协变量上平衡。研究了协变量分布对五种分配规则的性质的影响，重点是比较方法，这些方法也适用于其他形式的响应。可接受性的概念表明，广泛使用的最小化规则不如从最优实验设计理论导出的阿特金森规则。我们提出了这个规则的简化形式。对于这个规则，随着研究规模的增大，猜测下一个治疗分配的能力会降低。对于其他规则，它是不变的。
