Purity–completeness trade-off for primary RC selection under the common requirements ΔΠ_1,pred ≥ 250 s and Δν_pred < 5.5 μHz. The solid blue curve traces the locus as the ﹩{\sigma }_{{\rm{\Delta }}{{\rm{\Pi }}}_{1}}﹩ threshold is varied; red and yellow stars mark the adopted Tier 1 threshold of 20 s and Tier 2 threshold of 40 s, respectively. Gray squares and brown triangles show the two subsamples of M. Lucey et al. (2020) based on multiband photometry.