The dispersion of the Δm values (σ _l from Equation (4)) for our 14 CALSPEC standards (black curve). The calculation is performed in bins of 40 wavelength samples in order to lower the uncertainty on the individual Δm values for stars with fewer (STIS and/or SNIFS) observations. Overplotted are the dispersions when comparing filter photometry for the UBVRI filters (Bohlin & Landolt 2015; BL15 magenta diamonds). We have updated the UBVRI intrinsic dispersion, including subtraction of the quoted filter photometry measurement uncertainty, to include newer space-based CALSPEC standard stars (green squares). We also plot a similar comparison that we have done for Pan-STARRS1 in the griz filters. These points have been offset slightly in wavelength for clarity. This demonstrates that the dispersion of Δ m values determined from our Bayesian hierarchical standardization model are consistent with other external checks of CALSPEC.