Characterization of the biases and relative uncertainties in the velocity dispersions of the CALIFA survey. Top panel: ratio between the CALIFA and DMS/ATLAS3D measurements at the locations of the DMS/ATLAS3D values (see Sect. 5.2 for details). Bottom panel: relative uncertainties in the velocity dispersion values of the CALIFA survey using the Voronoi values and uncertainties for all the galaxies presented here. In both panels, the area delimited by the dotted lines indicates the 16% and 84% percentiles of the distribution of gray points. The solid lines and gray points indicate the median of the distributions.