Fraction of accepted group members and field stars in the sample as a function of the adopted value for ϵ_min. Circles denote field stars and triangles cluster members. Open and filled symbols represent the results obtained with the classic and new CPSMs, respectively. The vertical dashed line marks ϵ_min = 0.954. Each point represents the average value of 100 Monte Carlo simulations for a cluster with (l,b) = (180°,0°) and d = 100 pc.