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FDR‐controlling testing procedures and sample size determination for microarrays
Author(s) -
Li Shuying S.,
Bigler Jeannette,
Lampe Johanna W.,
Potter John D.,
Feng Ziding
Publication year - 2005
Publication title -
statistics in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.996
H-Index - 183
eISSN - 1097-0258
pISSN - 0277-6715
DOI - 10.1002/sim.2119
Subject(s) - sample size determination , false discovery rate , statistical power , computer science , sample (material) , multiple comparisons problem , statistics , data mining , mathematics , biology , gene , genetics , chemistry , chromatography
Microarrays are used increasingly to identify genes that are truly differentially expressed in tissues under different conditions. Planning such studies requires establishing a sample size that will ensure adequate statistical power. For microarray analyses, false discovery rate (FDR) is considered to be an appropriate error measure. Several FDR‐controlling procedures have been developed. How these procedures perform for such analyses has not been evaluated thoroughly under realistic assumptions. In order to develop a method of determining sample sizes for these procedures, it needs to be established whether these procedures really control the FDR below the pre‐specified level so that the determined sample size indeed provides adequate power. To answer this question, we first conducted simulation studies. Our simulation results showed that these procedures do control the FDR at most situations but under‐control the FDR when the proportion of positive genes is small, the most likely scenarios. Thus, these existing procedures can overestimate the power and underestimate the sample size. Accordingly, we developed a simulation‐based method to provide more accurate estimates for power and sample size. Copyright © 2005 John Wiley & Sons, Ltd.