Figure 4From: Evaluation of the similarity of gene expression data estimated with SAGE and Affymetrix GeneChipsScaling of two gene expression profiling platforms. Illustration of the steps involved in the scaling of values in each of the platforms to a common scale. The procedure takes the ratio distribution in one of the platforms and scales the other to match the same range of ratio values using a quadratic equation based on ratio 1 and the 10th and 90th percentile values of each platform. The (scaled) ratio values are then used to calculate between-platform ratio differences per transcript. In addition, it is demonstrated how the ratio differences can be used to calculate the standardized between-platform log(ratio) difference and a probability value. For further details: see the Materials and Methods section.Back to article page