Adaptive and nonadaptive group sequential tests
Adaptive and nonadaptive group sequential tests
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DOI：
10.1093/biomet/93.1.1
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发表时间：
2006-03-01
期刊：
影响因子：
2.7
通讯作者：
Turnbull, BW
中科院分区：
文献类型：
--
作者：
Jennison, C;Turnbull, BW
已经提出了在中期阶段重新设计临床试验以增加功效的方法。为了保持第一类错误率，必须根据不充分的统计来定义计划外设计更改的方法，这就使人们对其效率和得出结论的可信度产生了疑问。我们评估了适应性重新设计方案，扩展了使用Tsiatis和Mehta（2003）的充分统计数据的理论论据，并通过最佳测试的数值计算评估了预先规划的适应性设计的可能好处；这些最优自适应设计是Schmitz（1993）提出的最优顺序计划顺序试验的具体例子。我们的结论是，计划外适应性设计的灵活性是有代价的，我们建议在一开始就尽可能彻底地确定研究的适当功率。然后，标准的错误消耗测试，可能是不均匀间隔的分析，提供有效的设计，但仍然有可能依靠灵活的方法来重新设计，应该研究客观变化，一旦试验正在进行中。
Methods have been proposed for redesigning a clinical trial at an interim stage in order to increase power. In order to preserve the type I error rate, methods for unplanned design-change have to be defined in terms of nonsufficient statistics, and this calls into question their efficiency and the credibility of conclusions reached. We evaluate schemes for adaptive redesign, extending the theoretical arguments for use of sufficient statistics of Tsiatis & Mehta (2003) and assessing the possible benefits of preplanned adaptive designs by numerical computation of optimal tests; these optimal adaptive designs are concrete examples of optimal sequentially planned sequential tests proposed by Schmitz (1993). We conclude that the flexibility of unplanned adaptive designs comes at a price and we recommend that the appropriate power for a study should be determined as thoroughly as possible at the outset. Then, standard error-spending tests, possibly with unevenly spaced analyses, provide efficient designs, but it is still possible to fall back on flexible methods for redesign should study objective change unexpectedly once the trial is under way.