Left panel shows the time dependence of the physical fraction of stars in clusters (gray lines; the same as Figure 1) and the estimated observed fraction of stars in clusters when using r_search = 5 pc (blue lines) and r_search = 2 pc (green lines). The cluster mass is indicated by the line style. The right panel shows the time dependence of the physical fraction of stars in clusters (solid lines) and the estimated observed fraction of stars in clusters assuming r_search between 2 to 5 pc (filled areas). This panel is for the ECMF of Eq. (4) with β = 1.5 (magenta), β = 2 (black), and β = 2.4 (yellow).