Figure 1  ROC curve comparing the performance (sensitivity) of different ranking methodologies in identifying differentially expressed genes in spike-in data. (A) Comparison of our approach (median t-values) with different preprocessing methods used with t-test as ranking method to select the differentially expressed genes. (B) Comparison of our approach (median t-values) with the best performance of other ranking methods: t-test, SAM and LIMMA. The best performance of t-test, SAM and LIMMA is obtained when using RMA as a preprocessing algorithm.