The points are equal number (10,000) bins of FRBs according to the maximum posterior probability of their host candidates for SB-1. For each set of 10,000, we determined the fraction of correct assignments if one adopts the candidate with max ﹩P\left({O}_{i}| x\right)﹩ as the host. The one-to-one line indicates a perfectly calibrated algorithm. The colors indicate different choices for the prior P(O): (blue) P(O) ∝ 1/Σ(m), inverse; (orange) P(O) ∝ 1/Σ(m)ϕ, inverse1; and (green) P(O) ∝ 1/Σ(m)ϕ², inverse2. Our adopted prior (inverse) is relatively well normalized in that ﹩P\left({O}_{i}| x\right)﹩ yields an accurate estimate of the fraction of FRBs correctly assigned to their host galaxy.