Recovery of original effect using different normalization methods. Effects of different normalization methods for diagnostic microarrays evaluated on simulated data. " + " depicts expression differences in the test data of the signature genes after normalization with all 3000 genes. This, we would like to recover with normalization methods for diagnostic microarrays, too."o" corresponds to using the standard protocol on the diagnostic microarray. Here, all the signal is lost, "r" corresponds to a normalization of the diagnostic microarray with 10 random genes. It already recovers the signal partially. The right plot is a closeup of the left plot, showing additionally the performance of the proposed normalization schemes. " + " and "r" are the same as in the left plot. Additionally, normalization using lowest variance "v", smallest difference "d", smallest coefficient of variation "c" and balanced signatures "b" are shown. For better visibility the symbols "b" and "d" are slightly moved to the side so that they do not overlap.