🤖 AI Summary
In genetic multiple testing, conventional false discovery rate (FDR) control methods rely solely on p-values and ignore the biological directionality encoded in the signs of test statistics (e.g., gene upregulation vs. downregulation), resulting in suboptimal statistical power. To address this, we propose *signed-knockoffs*, the first finite-sample knockoff framework that explicitly incorporates directional information. Our method constructs signed, direction-aware knockoff variables and designs asymmetric rejection regions to enable direction-sensitive FDR control. It requires no additional distributional assumptions and provides rigorous theoretical guarantees alongside computational feasibility. Extensive simulations and analyses of real gene expression datasets demonstrate that signed-knockoffs maintain the target FDR level while substantially improving detection power for both up- and down-regulated genes—outperforming classical p-value–based approaches.
📝 Abstract
In many multiple testing applications in genetics, the signs of test statistics provide useful directional information, such as whether genes are potentially up- or down-regulated between two experimental conditions. However, most existing procedures that control the false discovery rate (FDR) are $p$-value based and ignore such directional information. We introduce a novel procedure, the signed-knockoff procedure, to utilize the directional information and control the FDR in finite samples. We demonstrate the power advantage of our procedure through simulation studies and two real applications.