Mean ratio, R(λ), of observed flux to pipeline-model flux as a function of observed wavelength for quasar spectra to the red of the Lyα emission line (λ_RF> 130 nm). (The mean is calculated by weighting each measurement by the inverse of the pipeline variance.) In this mostly unabsorbed region of quasar spectra, the percent-level wavelength-dependent deviations from unity are due to imperfect modeling of calibration stars and to the calcium H and K lines (393.4 and 396.9 nm) due to Galactic absorption.