Figure 1. a) True positive rate, b) false positive rate, and c) net assignment value for assignment of taxa to the core by four different core assignment methods. Individual 5x5 heatmaps represent 6,250 simulations each. Each square within a heatmap represents 250 simulations at one of the possible 25 combinations of intensity (θ = 1 corresponding to low precision in taxon abundance, and 2, 10, 25, 50 corresponding to increasing precision in taxon frequency), and ratio of the abundance of core to non-core taxa (1, which is a simulation with no difference in the expected taxon frequencies, and 2, 5, 10, 25 that corresponding to greater differences in the frequency of core and non-core taxa). The top row a) presents true positive rates, giving the probability that taxa simulated with core characteristics were recovered as such. A true positive rate of 1 means all 25 true core taxa were assigned as such. The middle row b) presents false positive rates or the probability that non-core taxa were assigned as core. A false positive rate of zero represents simulations when no non-core taxa were assigned to the core, whereas a rate of 1 indicates all non-core taxa were incorrectly assigned to the core. The bottom row c) presents the net assignment rate, an absolute value of true positives – false positives for each of the four methods. A positive net assignment rate indicates better performance, while larger negative numbers indicate poorer assignment of core membership.