Comparison of normalization procedures: Goodness-of-fit of Poisson model. The multiplicative Poisson model (GLM 1 in [Additional file 2: Supplemental Table S4]) is fit to the seven Brain lanes in the MAQC-2 experiment after (a) total-count, (b) POLR2A, (c) upper-quartile, and (d) quantile normalization. Goodness-of-fit statistics are computed and displayed in χ2 quantile-quantile plots. Genes with goodness-of-fit statistics in the top quantiles of the χ2-distribution are displayed using colored plotting symbols: red (1, 5]%, purple (.1, 1]%, gold [0, .1]%. Similar plots for UHR show the same patterns.