Absolute bias and dispersion for the effective radius of bulge (left column) and disc (right column) components in the double-Sérsic simulation, as a function of bulge-to-total ratio (x-axis) and apparent I_E magnitude (y-axis). Each row shows a different code. For ProFit and Galapagos-2, the colour scale is logarithmic. In each panel, the colour of the squares is proportional to the mean bias 𝒟 (lighter being smaller), and the colour of the dot inside each square indicates the dispersion 𝒟 (redder being lower). For most of the codes, we find the expected behaviour: both the bias and the dispersion increase for faint objects, as well as at small b/t for bulges and large b/t for discs.