Left: distribution of real cluster probabilities vs. CI. Sizes vary according to the initial masses (bigger size means larger initial mass) and colors according to the distance (see colorbar to the right). Circles represent values for SOCs and diamonds values obtained for field regions. Right: logarithm of the CI vs. relative error for the true number of members and that predicted by ASteCA for each SOC. Point markers are associated with ages as shown in the legend. The shaded region marks the range where 50% of all SOCs are positioned.