Variation in the mean and standard deviation of the TRGB magnitude as a function of the GLOESS smoothing parameter. The vertical grey lines indicate the range over which the absolute magnitude of the TRGB is insensitive to the smoothing value, according to A24 for their ‘SARGs’ sample. The orange shaded region was determined for the GC sample using the criterion $\left|\frac{d{M}_{R{P}_0}}{d{\sigma }_s}\right|\le 0.10$ and covers the range σ_s ∈ [0.08, 0.18] mag.