Simple nomograms to calculate sample size in diagnostic studies
Simple nomograms to calculate sample size in diagnostic studies
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DOI：
10.1136/emj.2003.011148
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发表时间：
2005-03-01
影响因子：
3.1
通讯作者：
Harrison, M
中科院分区：
文献类型：
--
作者：
Carley, S;Dosman, S;Harrison, M
目的：制作一种易于理解和易用的工具，供研究人员在诊断研究中使用。诊断性研究应该进行样本量计算，但在实践中，它们很少进行。结果：诺模图可以很容易地用于确定一项测试的灵敏度和特异度。结论：诺模图除了易于使用外，还允许在已知其他三个参数的情况下推断缺失的参数(患者数、可信区间、患病率或灵敏度/特异度)。诺模图也可以被已发表研究的读者回溯使用，作为计算样本量的粗略估计工具。
Objectives: To produce an easily understood and accessible tool for use by researchers in diagnostic studies. Diagnostic studies should have sample size calculations performed, but in practice, they are performed infrequently. This may be due to a reluctance on the part of researchers to use mathematical formulae.Methods: Using a spreadsheet, we derived nomograms for calculating the number of patients required to determine the precision of a test's sensitivity or specificity.Results: The nomograms could be easily used to determine the sensitivity and specificity of a test.Conclusions: In addition to being easy to use, the nomogram allows deduction of a missing parameter ( number of patients, confidence intervals, prevalence, or sensitivity/ specificity) if the other three are known. The nomogram can also be used retrospectively by the reader of published research as a rough estimating tool for sample size calculations.