Constraints to both residual mass (A_m) and redshift (A_z) dependencies, as defined in Eq. B.1. In the figure, we plot the distribution of the intrinsic scatter of the combined HIGHMz – REXCESS – ESZ sample, as a function of A_m (top) and A_z (bottom). In the upper panel, measured points are colour coded according A_z, while in the lower one according to A_m values. Vertical red lines mark the positions of the two minimum values, while black ones are predictions from the self-similar scenario (i.e. A_m = A_z = 0).