VALIDITY ISSUES IN SPLIT-MOUTH TRIALS
VALIDITY ISSUES IN SPLIT-MOUTH TRIALS
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DOI：
10.1111/j.1600-051x.1992.tb01709.x
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发表时间：
1992-10-01
影响因子：
6.7
通讯作者：
DEROUEN, TA
中科院分区：
文献类型：
--
作者：
HUJOEL, PP;DEROUEN, TA
裂口设计的主要目的是从治疗比较中删除与受试者之间差异相关的所有组分。通过进行患者内比较，而不是患者间比较，可以减少实验的误差方差（噪声），从而获得更强大的统计检验。不幸的是，在患者内进行的比较有潜在的缺点。处理可能会对实验单位产生影响，而不是它们被分配到的实验单位（交叉效应）。这种影响无法从裂口数据中估计出来。治疗效果也无法估计。裂口设计中的可估计参数是处理效应加上所有携带效应之和。除非先验知识表明不存在交叉效应，否则报告的治疗疗效估计值可能存在偏倚。在裂口临床试验的设计中。精确度的潜在提高应与有效性的潜在降低仔细权衡。
The main purpose of the split-mouth design is to remove all components related to differences between subjects from the treatment comparisons. By making within-patient comparisons, rather than between-patient comparisons the error variance (noise) of the experiment can be reduced, thereby obtaining a more powerful statistical test. Unfortunately, comparisons made on a within-patient basis have potential disadvantages. Treatments may have effects on experimental units other than those which they were assigned to (carry-across effects). Such effects cannot be estimated from split-mouth data. Neither can treatment effects be estimated. The estimable parameter in a split-mouth design is the treatment effect plus the sum of all carry-across effects. Unless a priori knowledge indicates that no carry-across effects exist, reported estimates of treatment efficacy are potentially biased. In the design of split-mouth clinical trials. potential gain in precision should be carefully weighed against a potential decrease in validity.