Results of the stacked analysis on simulated catalogs of lensed galaxies that mimic our observations for the full sample of 80 strong lenses. Colored triangles show the best-fit mass and concentration for the three composite lenses corresponding to stacks in richness. The gray-shaded area covers the intrinsic dispersion of the simulated lenses (black stars) around their average mass and concentration. The overlap of these average values with the results of the stacked analysis indicate the absence of any strong systematic bias.