Two-stage experimental designs : early stopping with a negative result
Two-stage experimental designs : early stopping with a negative result
复制标题
两阶段实验设计：早期停止，结果为阴性
DOI：
--
复制
发表时间：
1992
期刊：
影响因子：
--
通讯作者：
G. Anderson
中科院分区：
文献类型：
--
作者：
M. Pepe;G. Anderson
我们提出了两阶段实验设计，如果第一阶段结果不乐观，可以提前终止。这些组序贯设计具有第一阶段检验统计量的边界，这些边界相当于条件功效的临界值，在给定初始数据的情况下，根据合理但乐观的替代方案计算得出。即使名义第二阶段显着性水平未经调整，该程序仍保留合理临界值的功效。我们提供调整第一级参数的设计，以准确实现指定的尺寸和功率。推导了最小化 Hő 下的预期样本量的设计参数的选择，并且在直观上显示出没有吸引力，这表明选择基于最小化 Hő 下的预期样本量的设计可能是不合理的。
We propose two‐stage experimental designs which allow for early termination if the first‐stage results are not promising. These group sequential designs have boundaries for the first‐stage test statistic which are equivalent to critical values for conditional power, calculated under a plausible but optimistic alternative, given the initial data. The procedures preserve power for reasonable critical values, even if the nominal second‐stage significance levels are unadjusted. We provide designs which adjust the first‐stage parameters to achieve specified size and power exactly. The choice of design parameters minimizing expected sample size under Hő are derived and are shown to be intuitively unappealing, suggesting that choosing a design based on minimizing expected sample size under Hő may be unreasonable.