Detailed analyses of different subgroups of methods. Quadrant plots showing more detailed analyses of different subgroups of methods. Elements are coloured by group; black vs. red, as indicated in the figure titles. Black p-values indicate the significance with which "black" methods outperform the "red" methods and red p-values the opposite. Lines between elements indicate a pairing of variables for the statistical tests used. The following groupings are used: a. global vs. local estimations of normalisation parameters, b. non-zero vs. zero offsets and c. scaling using the central location vs. the dispersion of data.