Calibration of Gaia RVs for stars in common with APOGEE, GALAH, GES, and RAVE as a function of G mag derived by fitting a second degree polynomial (Eq. (5)). The blue and red points represent the median ΔRV of each bin with > 10 entries before and after the calibration respectively. The grey points are the binned ΔRV of the fit. The blue and red shadowed areas are the MAD of each bin. The bottom panels of each plot show the number of stars in each bin.